RAW if the spell has a S or M he has to have an empty hand to cast it and M he either needs to have an arcane focus or a component pouch. He does not need the arcane focus in his hand, he just needs his hand empty, manipulating the arcane focus or component is part of the cast action. To do this you can drop your weapon after you attack with it or you can stow it as a free action if you have not used your free action.
Hex is a 1st level spell that lasts an hour and it combines with the cantrips you will be using. It is not as powerful as shadowblade by itself, but it will last longer, does not require a second level slot and works with the cantrips. Until you reach 6th level in BS, you will do more damage with hex and a cantrip than with shadowblade. Blur is another concentration spell you should think of getting.
One thing that nerfs shadowblade in this build is you can't use it to cast booming blade or green flame blade. Below 5th character level, using shadowblade you will do the same damage as booming blade with a Rapier (assuming the enemy moves) and without using concentration or a spell slot. Once you make 5th level (character level) you do more with booming blade and significantly more with Green Flame Blade (assuming 2 targets). When you get to 6th level in BS you can attack with the shadow blade, then casting booming blade using another weapon. Here and above shadowblade will outrun booming blade+hex although you have to game the two weapon concern you note above. In this I did not consider the advantage shadowblade can give in certain lighting.
I have a V. Human so I already have fey touched. My planned progression is R1-BS2-AT3-BS6-AT7 that will be 13th level and that is where the campaign will end.
He wont allow me to drop the weapon and bring it again in the next turn as 2 free actions bcs he said only warlock have arcane focus on the sword and thats have to matter lol, but he allowed me to use booming blade on shadow blade, and anyway ill get acquamarine asap.
About hex, using it for 6 lv is good, but after that i dont think it can be changed anymore, but well, yea, i see your point here.
I think if you want to play a melee Rogue with great defense 6th level in Wizard is a nice stopping point. Agree with what you said about uncanny dodge and evasion, but if you stop at 3 you are missing an ASI at 4 and expertise at 6. For me expertise is the big reason to go past 3 and that is worth 2 wizard levels.
As i said this is a nice build for a rogue, and it can probably focus on shadow blade more than a straight bladesinger, with a kinda huge ammount of malee damage (one turn: 3d8 shadow blade + 1d8 second attack + 2d8 BB + 7d6 sneak +10 +1d8 hopefully off hand attack, for a total of 70 per turn with no crits) and probably being better than a pure arcane trickster all the way, so ill cosider also it.
I played a single class bladesinger several times. I did not use it like any other wizard, really completely the opposite of a regular wizard. To start with she has more defensive spells in the build and fewer offensive spells. You do have powerfull spells you use to take down bosses and large numbers, but you are not using lowlevel offensive spells in every battle like most wizards. You are using low level defensive spells instead. The biggest difference in my games is she was in the very front, ahead of the martial characters even, where a traditional wizard is typically in the very back. When you deploy your nukes as a Bladesinger you do it from the front line.
Both of the bladesingers I have played were the character in the party that went into melee range first. They did not do a ton of damage up there unless they were throwing a lighting bolt or cone of cold or something but they were always the ones trying to draw the enemy attacks because they are very hard to hit. That is their role, get as many enemy as possible to atttack them and not other party members.
A lot of people on this board don't like that style but it works very well in my experience. A multi class rogue will not be as effective at that because you get less spells and will run out of spell slots to cast shield. You will need to play more like a Rogue and be tactical about where you insert yourself where a single class bladesinger charges straight into the thickest part of the battle.
Yes i understand it, but you are just confirming that a bladesinger for deal damage mostly dont use a blade...and thats kinda weird in my opinion, i think he should alternate good or decent dpr with malee (i honestly dont know if compared with a barbarian or fighter it is near from this point but i think probably no, neither using spellcast abilities for focus on melee, bcs it have to be said that for stay in melee he need to spend resources that many other wizards dont need that much or that anyway they use much less often, keeping their slots much more free) and support party members (till get simulacrum that make he do both things in one turn! Bigby's hand and shadowblade together? he can, haste and shadow blade together? Yes pls! Make my ally become a Trex while using shadow blade? omg yes! Have shadow blade and haste both while the simulacrum cast again a spell in the turn that can be whatever and the character have a spell action plus an attack with shadow blade? thats near to be unbelieveble lol...), thats the bladesinger i have in mind.
Between Bladesinging, Shield, and Absorb Elements, I was the least able to be hit. Getting into melee and keeping foes tied up was important. (Also, we found Bracers +2, so I dropped back from light armor to Mage Armor.) I was tanking more than damaging, though that was pre-Tasha's and being able to mix in a cantrip would have helped. That would have moved me to 4d8+14 plus 3d8 more on a move per turn. (d8+7 base with my +2 rapier, one with booming blade)
Avernus has a lot of magic resistant, multi-elemental resistant/immune foes. So anything with a save and much elemental damage was deprioritized. Helped keep me on track. But I also prioritized DEX over INT to help keep me on track.
The only thing that was more "standard caster" is that I had planned Concentration spells like Greater Invisibility to buff my fighting, but more often we I would be doing things like upcasting Fly on our melee characters (including myself) or throwing out a Wall of Force while we're fighting another Infernal War Machine. Counterspell I could like Shield or Absorb Elements - defensive magic fine with Bladesinging. Oh, an casting Dragon's Breath on my Familiar.
Some things I that I consider falling under bladesinging as much as "standard casting" includes reaction defenses liek Shield, Absorb Elements and Counterspell, and thinks like Transmute Rock to mire opponents while I was flying. And any spell that buffs my melee attacks.
Final battle with [REDACTED, but after the obvious] was fun - only one we got to prep for. We had a Heroes' Feast up, but I had up Fire Shield (Chill), Crown of Stars, and Tenser's Transformation. The last was the only casting of the game, and it nerfed me not being able to Misty Step or cast reaction spells enough that I probably wouldn't again, but it was pretty glorious since auto-advantage plus Elven Accuracy plus +2d12 forcde damage per hit turned me into such a powerhouse.
Yea its for sure a good tank even with few hp (he suffer a lot cha savings, but cant have everything), even probably a sorceradin do it better and deal consistent damage more.
Spell buffing malee attacks are shadow blade, BB, GFB, maybe enlarge (just 1d4), Spirit Shroud, haste and tenser transformation, plus maybe some not wizard spells, a paladin spell that gives 2d6 damage, hunter mark, hex...but all require concentration, so, having to choose seem that mostly of times shadow blade looks better, or i can think about a very mobile build with longstrider, bladesong and maybe mobile feat (or maybe not), for a total boost of my speed up to 30 feet (plus for sure haste)...he ll become an anticaster, he ll still increase his AC, going to get the casters in the backline. This make this build haste and counterspell focused, so no shadow blade at least till lv 13, when simulacrum can haste me and probably would fit better with a TWF (even without the feat). Other way is cast shadow blade and give up haste, or maybe use GI and rapier, but this last one seem already suboptimal.