I think the assassin is the wrong rogue to look to for comparison, anyway. There's too big a difference between average damage with a nova first round and without. A swashbuckler will get sneak attack more often, by virtue of more easily moving around the battlefield and having an extra way to get sneak attack, and the assassin won't get their nova strike every combat, and only once per combat when they do get it. 95% of the time, the assassin might as well not have a subclass, when it comes to DPR. The damage output when they do make use of their subclass just doesn't make up for that.
Arcane Trickster also works, because spells can help output more damage. Booming Blade combined with Mobile (or Swashbuckler with Magic Initiate or a cantrip from being a High Elf) adds extra damage when you've got advantage, and then you just dual wield for when you don't have advantage and the enemy has high AC.
The other thing you want to max out DPR on a rogue is to increase the frequency of making a reaction attack off your turn. For that, you want feats. Since you can't use staves or spears for SA by RAW, PAM is out, but Sentinel works fine, as does Mage Slayer. Lots of monsters cast spells, and a Swashbuckler is hard to keep away from.
Anyway, yes, haste+hex/hunter's mark+flurry of blows+hexblade's curse etc is quite good.
Yes, you are correct about the assassin not being a good comparison, that's why in the damage tables I set up I included a section for rogues that do not get auto crit. Those sections also includes the sneak attack damage. My intention was that those sections were to be assumed for swashbucklers since they get sneak attack practically every round, just no auto crit. But yes, I probably should have just labelled the two sections "Assassin" and "Swashbuckler."
As for booming blade, yes it is good damage on rogues but even then it doesn't bring the damage of a swashbuckler up to the damage of Monklock. Here are some new comparisons, corrected for less attacks per action, and haste being one attack. I will also do a standard set of stats instead of arbitrarily setting them. "
Lvl 12 Rogues + Booming Blade + Haste + Flametongue
[TABLE="class: grid, width: 1000, align: center"]
[TR]
[TD][/TD]
[TD]Action (B. Blade)[/TD]
[TD]B. Blade Damage[/TD]
[TD]B. Blade Move[/TD]
[TD]Haste[/TD]
[TD]Sneak Attack[/TD]
[TD]Flametongue[/TD]
[TD]Dex[/TD]
[TD]Minimum[/TD]
[TD]Average[/TD]
[/TR]
[TR]
[TD]Assassin[/TD]
[TD]2d8[/TD]
[TD]+4d8[/TD]
[TD]+6d8[/TD]
[TD]+1d8[/TD]
[TD]+12d6[/TD]
[TD]+6d6[/TD]
[TD]+10[/TD]
[TD]45[/TD]
[TD]131[/TD]
[/TR]
[TR]
[TD]Swashbuckler[/TD]
[TD]1d8[/TD]
[TD]+2d8[/TD]
[TD]+3d8[/TD]
[TD]+1d8[/TD]
[TD]+6d6[/TD]
[TD]+4d6[/TD]
[TD]+10[/TD]
[TD]27[/TD]
[TD]77[/TD]
[/TR]
[/TABLE]
Under assassin, I have B. Blade Move as the damage for when the target moves. The critical (2x dice) applies to the attack of b. blade, the flametongue dice, and the b. blade damage/movement damage. The b. blade critting does add a lot of damage clearly, but as stated before this occurs one time in a fight.
Now here is the Monklock again. Corrected stats, attack actions, and even levels. Before, I was using 7 Kensei and 5 Hexblade, but those levels were just picked to reach evasion/stillness of mind on the monk. Technically, those 2 levels don't get any more damage output from monk. The new build is as follows:
Level 12 Character
5 Paladin, 5 Kensei, 2 Hexblade.
Yes, there is an overlapping extra attack from monk/pal that gets wasted. Paladin oath doesn't matter here, I am using pal to get spell slots and divine smite for more damage. I believe paladin would also be able to use their spell slots for warlock spells if need be.
Stats: Wood Elf, 2 ASI's for stat increases
[TABLE="class: grid, width: 300, align: left"]
[TR]
[TD]Str[/TD]
[TD]14[/TD]
[/TR]
[TR]
[TD]Dex[/TD]
[TD]20[/TD]
[/TR]
[TR]
[TD]Con[/TD]
[TD]10[/TD]
[/TR]
[TR]
[TD]Int[/TD]
[TD]8[/TD]
[/TR]
[TR]
[TD]Wis[/TD]
[TD]14[/TD]
[/TR]
[TR]
[TD]Cha[/TD]
[TD]13[/TD]
[/TR]
[/TABLE]
The main focus Here is to be able to achieve 20 dex. I know it's a waste of hexblade's ability to use Cha for attacks. That's fine. The hexblade is being used for their baleful curse, which adds proficiency as a damage bonus. This character probably wouldn't have amazing saving throws, or an amazing AC at this point, but I am experimenting here purely in the quest for more damage output, nothing else.
Kensei Weapon is rapier, hexblade makes the flametongue a pact weapon which gives it a +1 bonus as well, from the improved pact weapon invocation.
Maladinlock + Haste + Flametongue + Hex + Baleful Curse + Divine Smite on each weapon attack
[TABLE="class: grid, width: 1000, align: center"]
[TR]
[TD]Action[/TD]
[TD]Haste[/TD]
[TD]Divine Smite[/TD]
[TD]Flurry of Blows[/TD]
[TD]Hex[/TD]
[TD]Flametongue[/TD]
[TD]Dex[/TD]
[TD]Proficiency[/TD]
[TD]Pact Weapon[/TD]
[TD]Minimum[/TD]
[TD]Average[/TD]
[/TR]
[TR]
[TD]2d8[/TD]
[TD]+1d8[/TD]
[TD]+6d8[/TD]
[TD]+2d6[/TD]
[TD]+5d6[/TD]
[TD]+6d6[/TD]
[TD]+25[/TD]
[TD]+20[/TD]
[TD]+3[/TD]
[TD]70[/TD]
[TD]143[/TD]
[/TR]
[/TABLE]
This is only sustainable as long as there are paladin smites, which is not very long. A level 5 paladin has 6 slots. Assuming every attack lands, this character runs out of smites in 2 rounds. After which they default to this damage output:
[TABLE="class: grid, width: 700, align: center"]
[TR]
[TD]Action[/TD]
[TD]Haste[/TD]
[TD]Flurry of Blows[/TD]
[TD]Hex [/TD]
[TD]Flametongue[/TD]
[TD]Dex[/TD]
[TD]Proficiency[/TD]
[TD]Pact Weapon[/TD]
[TD]Minimum[/TD]
[TD]Average[/TD]
[/TR]
[TR]
[TD]2d8[/TD]
[TD]+1d8[/TD]
[TD]+2d6[/TD]
[TD]+5d6[/TD]
[TD]+6d6[/TD]
[TD]+25[/TD]
[TD]+20[/TD]
[TD]+3[/TD]
[TD]64[/TD]
[TD]116[/TD]
[/TR]
[/TABLE]
This table here, is sustainable as long as there are ki points for the monk side of things to spend on flurry of blows. Which is 5 rounds. So in short, you deal 140 damage for two rounds, and then 115 for another 3 rounds after that. What I like about this is that the divine smites can not get wasted. If the attack doesn't hit, there is no divine smite being used. Technically it's not a spell either, or concentration for that matter. Also, the other rogue tables from earlier are still valid. I don't think any math was done wrong on them. The rogues were only getting 1 attack from haste and using TWF and whatnot.
And to be honest, without these damage buffs, this character is still an effective damage dealing option. Clearly, other things might possibly be better at that point, but Maladinlock would still be effective in their own right after running out of all of their cheesey damage buff options.
Here is Maladinlock without haste, flurry of blows, or divine smite. They still have a flametongue, hex, and baleful curse however.
[TABLE="class: grid, width: 700, align: center"]
[TR]
[TD]Action[/TD]
[TD]U. Attack[/TD]
[TD]Hex[/TD]
[TD]Flametongue[/TD]
[TD]Dex[/TD]
[TD]Proficiency[/TD]
[TD]Pact Weapon[/TD]
[TD]Minimum[/TD]
[TD]Average[/TD]
[/TR]
[TR]
[TD]2d8[/TD]
[TD]+1d6[/TD]
[TD]+3d6[/TD]
[TD]+4d6[/TD]
[TD]+15[/TD]
[TD]+12[/TD]
[TD]+2[/TD]
[TD]39[/TD]
[TD]63[/TD]
[/TR]
[/TABLE]
If everything hits over the 5 rounds and each one has all the buffs, Maladinlock can deal upwards of 630 damage. In 5 rounds, the swashbuckler with booming blade would deal upwards of 380 damage.
All in all, not a terrible build in my opinion. I think it does damage effectively, and quite a lot of it. You could also go for even less sustain, and have something like 5 paladin, 2 warlock, 3 barbarian, 2 monk as well. To be honest though, it's mostly just a silly joke build. I don't really think anyone would, or even should, play something like this in a serious/dedicated campaign. I'm not saying it couldn't be fun, or that it wouldn't be effective. Both of those things are certainly possible. However, I mostly just wanted to explore ways to deal more damage. I think it's likely that if someone wanted a really high damage character that was still really fun, the Sorlock with Quickened EB would probably be better than this. And of course more sustainable at level 12 since they would have 10 sorcery points with 10 levels in sorcerer.
I do want to reiterate that this character was also designed to scale harder than other classes. As in, utilize damage buffs/steroids more efficiently than other classes. I think it's largely accomplished this goal. For example, if you hand a Flametongue to the EB Sorlock they don't get any more damage output. It's a sword, I know, but I don't know of any magic items that would add flat damage to their cantrip. If you cast haste on the Sorlock, they don't get any more damage because you can't use haste to cast a spell. Haste also adds very little damage to the rogues since most of their damage is from sneak attack anyway, which only ever procs once per turn. You get the idea.
Anyway, let me know what you guys think. I think it's fun to talk about builds and stuff, it's always interesting to come up with new ideas.