Thanks for the responses! Let's talk about some of the thoughts.
I would have liked to see you build this as a proper half-caster. A fighter/wizard in 2E wouldn't have had as high of a wizard level as a single classed wizard, no?
5e only has three types of standard spell slot casters. Full, half, and third. Half was not at all sufficient for what this class is supposed to be. My attempts at the AD&D/Gestalt style would have made something less than full, but they didn't work. So full it was.
The first thing that jumped out at me was the Extra extra attack at 18th level. It seems out of place. Paladins don't have it, Rangers don't have it, should this half-caster have it?
A few people have mentioned this one, which is good, because it is one of the features I'm most ready to jettison. Assuming that your standard at-will attack is War Magic using
green-flame blade or
booming blade, the third attack generally doesn't do as much damage. It really is only situationally useful--like if you are using your bonus action for Second Wind or something else and so can't benefit from War Magic.
Conceptually, I threw it in there because more than one extra attack is a fighter thing, and this stresses their fighter connection. If it were actually as weak as I thought it was that would work out pretty well. Ie, I
want to be borrowing something only the fighter gets. If it is more useful than I'm giving it credit for, however, then it can easily go.
Full caster with wizard casting, which is the most flexible. Including the ritual castign that doesn't even need prepared that only wizards get. But with better HPs, armor and weapon, more features then wizard subclasses get, including some from the wizard subclasses, and the war magic boost from Eldritch Knight that is their single most defining characteristic.
If I take this and play it as a straight wizard, how am I not more powerful then a straight wizard?
You asked a great question, so I'll be quoting your post for a bit, but my comments are intended for everyone.
The premise is that you would be giving up these things from a wizard to to go warrior-mage instead:
-Arcane Recovery
-Subclass features
-Signature Spell+
-Single attribute dependency
Arcane Recovery: The wizard basically has one more spell of their highest spell slot up until 11th level. In 5e, that's a pretty big deal.
Subclass Features: Take, say, Abjurer. They get the ability to share their Arcane Ward, they get the ability to dispel and counter better, and they advantage on saves vs spells and resistance to their damage. (As far as the one you would get from warrior-mage, it isn't intended to be a strong feature. I nerfed the Abjurer version, and I could nerf some of the others if needed. Think of Minor Conjuration or Minor Alchemy--that's what the warrior mage version is supposed to be about.)
Signature Spell+: Instead of getting Spell Mastery at 18th level when it will still see plenty of use in a x-20th campaign, you would have to wait until 20th for it, and not get your extra two 3rd-level spells per short rest at that level.
Single Attribute Dependency: A wizard has nothing in the way of maxing out their Intelligence. This increase their spell save DC, which is a big deal (attack bonus doesn't seem as big of a deal to me, but hey it's there too). It also increases the number of spells prepared, which isn't as big as the save DC, but for a wizard, having as many spells prepared as possible is important.
And there's more. Once the wizard maxes out their Intelligence, they can plow all of the rest of their points into Dex (and then Con when they've maxed Dex) and get a better AC with a single
mage armor than a warrior-mage. The warrior-mage has to split their ASI's between an attack stat and Intelligence, which leaves them with poor AC for a frontliner. (If they go Dex and the DM lets them cast with a shield without much difficulty, their AC will be somewhat better.)
The question is, if your concept is "I want to be an awesome wizard", rather than, "I want to be a warrior-mage", how do you feel playing a wizard instead of a warrior-mage? Do you feel like you are getting ripped off, or do you feel like you're getting what you need and most of what they have is superfluous?
Because here is what they gain over you:
-Health Resources: Better HD, (Weakened) Second Wind
-Excellent At-Will Melee Weapon Damage: Fighting Style, Extra Attack, War Magic
-Indomitable Spirit
Health Resources: Better HD, (Weakened) Second Wind. You could put a little bit of AC in here if you think you'll have better AC as a warrior-mage (not to be assumed)
Excellent At-Will Melee Weapon Damage: Fighting Style, Extra Attack, War Magic.
Indomitable Spirit: Reroll one limited save per day that you probably aren't proficient in
Do you really care about those first two if you are a wizard? I wouldn't. If I were a wizard I wouldn't give up Arcane Recovery for d12 HDs and Barbarian Rage. While they might sound like a great feature, I have to give up something that directly enhances what I'm trying to do (ie, be the best (I'm not talking optimizing, just concept with mechanical awareness) wizard that I can be), for some other feature that lets me do something else unrelated. Am I alone on this one?
The second one is nice to have, but I'm not sure I'd want to give up anything I get as a wizard for it. (However, it is a warrior-mage feature that will be one of the first on the chopping block if I need remove some, since it isn't that integral to the class.)
So, given those considerations, what appeals most to you (this is a question for everyone), when you want to play a wizard? I know I can answer for myself that I'd play a wizard rather than a warrior-mage and not feel like I'm getting ripped off. But maybe I'm in a weird minority. I need more opinions on this one.
(And of lesser interest: If I take this and play it as a fighter with spells, how am I not more powerful then a Fighter (Eldritch Knight)?)
This one is trickier, because a lot of people will compare a fighter to a wizard and say the wizard is better, end of story. Well, there's nothing to do for that really. I think they are both fun, but it makes direct comparison hard. So let's take a look at it just for fun.
You want to be a fighter who also does some magic. That's your thing. Let's see what you give up to be a warrior-mage:
-Health Resources
-Action Surge
-Two ASIs
-(Full) Indomitable
-Partial Subclass Features
-More Attacks
-Less Attribute Dependency
Health Resources: You're losing a bigger HD, a better version of Second Wind, and Heavy Armor excellent AC without Dex investment.
Action Surge: Including the extra usage at high levels. This is a phenomenally useful ability.
Two ASIs: This goes along with a Less Attribute Dependency. You are maxing your attack stat fast. You hit better, harder, faster. And once you've maxed it out, probably at level 6, you can then put stats into in Intelligence (as a secondary stat--if you even want to worry about spells that use it) and Con. You will literally max all 3 of those stats before the warrior-mage maxes 2. If you go with Int before Con, you can stay
ahead of the warrior-mage in spell save DCs. You cast harder and faster too! I'm not even assuming feat usage here, so this is just ASIs (which is how I do comparisons).
Full Indomitable: You're giving up 3 uses that work on all of your saves, for 1 use that works on two of your saves.
Partial Subclass Features: You won't be giving up (Improved) War Magic, but you'll be giving up Weapon Bond (not much, but some usefulness), Eldritch Strike, and Arcane Charge--stuff that lets hit magically harder and magically hit faster.
More Attacks: Even if warrior-mage keeps the third attack at level 18, you're getting a third attack at level 11--when it matters. From levels 11-16, it is a better option to use three attacks against a target than to use War Magic with
green-flame blade or
booming blade. You can do this, warrior-mage can't. (And of course you get your capstone 4 attacks at 20th-level.) In fact, you are doing more at-will damage than a warrior-mage at almost every level, and that's not counting Action Surge.
Less Attribute Dependency: Covered already.
What are you gaining by going warrior-mage instead?
-
Way Better Spellcasting
-Arcane Specialization
-Sooner Improved War Magic
Way Better Spellcasting: As an eldritch knight you gain cantrips and 1st level spells at level 3, and end up with 4th level spells at level 19. That's nothing compared to a warrior-mage, who gets full casting with all the perks. They also get Spell Mastery at 20th level.
Arcane Specialization: Some of these are probably helpful for a fighter
Sooner Improved War Magic: A warrior-mage gets it at 14th level (like a bard) while you'd have to wait until 18th level as a fighter.
So I want to be a fighter who does some magic. Is warrior-mage more appealing?
The spellcasting is, of course, tempting for anyone. And getting Improved War Magic earlier is envy-provoking. But are they worth giving up what makes me a fighter? Not really. If I want to hit harder, faster, better; last longer; and excel at physical things; while having some magic to spice it up, I'd probably prefer to be an Eldritch Knight. Those 10th and 15th level features really let you do some cool stuff the warrior-mage can't. I realize this one is a harder sell.
So, given those considerations, what appeals most to you (this is a question for everyone), when you want to play a magic-dabbling fighter? I'd play an eldritch knight rather than a warrior-mage and not feel like I'm getting ripped off. But again, I need to know how others feel about it. And as an aside--would that change if it were Bladesinger vs. Eldritch Knight? (Because that kind of throws of the comparison, if you're willing to give up that much more to get what the Bladesinger does.)
Thanks for the discussion so far. I want to really tear into this thing and see what works or doesn't work.