Bladesinger build, dip fighter or rogue?

[Gnumaster]

So Im going to participate in a new campaign soon and the Bladesinger has intrigued me for a while. We rolled for attribute stats and this is what I have to work with:

17, 17, 16, 12, 10, 8

With stats like that I can get two attributes at 18 (3 if one of them is charisma by picking half-elf). We will probably start the campaing in level 2 and it is expected to run untill level 15i-16sh but could run longer.

The GM has made a few tweaks and of those the following has implications for a possible bladesinger build:

-If you dont pick variant human you get to start with one of the normally least used feats (including racial feats), one of which is Dual Wielder. If the feat includes an attribute increase you dont get that part of the feat.
-You DO get to make an off hand attack as a bonus action after casting Booming Blade or Green-Flame Blade as you action.
-It IS allowed to use Booming Blade or Green-Flame Blade as your hasted action (the extra action you get by casting Haste)

So with that in mind I think it might be time to try to build a dual wielding blade singer

The campaign isnt about min/maxing at all but I do like to build a character that is both fun to play and somewhat optimized. Going halv-elf is fine for Bladesinger race requirement and I expect to play that. As the campaign is expected to end at level 15-16ish level 16 is what I aim at and I will pick up Dual Wielder as the free starting feat.

Fighter dip (Figther 1 + Bladesinger 15 or Fighter 2-4 + Bladesinger 12-14)
Starting at fighter for 1 level for the extra HPs (wizards are squishy, getting second wind is decent as well), con saving throw and fighting style (Two-Weapon Fighting). Then going Bladesinger and if I at some point feel like it dip back into fighter for a 2nd level getting action surge or 3rd level getting martial archetype (Battlemaster). Level 11 Bladesinger will give 6th level spells and going 13 will give 7th. Warcaster is probably a must ASAP and getting +2 dex and and +2 int would be really nice, also getting Mobile seems really good when using Booming Blade just leaving an enemy stranded or taking extra damage if he wants to move! Maybe go Warcaster, Mobile and +2 dex for the first 3 ASI's and +2 int as the 4th ASI if we end up going level 16+.

I dont want to build a Fighter 13 + Bladesinger 2 character.

Rogue dip (Swashbuckler 3 + Bladesinger 13, SB 5 + BS 11. SB 7 + BS 9, SB 9 + BS 7, SB 11 + BS 5, SB 14 + BS 2)
Again going rogue for the first level and then 2 level Blademaster. After that either 2 more levels into Bladesinger for the ASI (getting warcaster) or back into rogue for a couple of levels to get Fancy Footwork (which is REALLY nice with Booming Blade) and Rakish Audacity. Swashbuckler is charisma based but cha doesnt seem TOO important (+ cha mod to initiative and Panache if going Swashbuckler to 9+) so I feel like I can get by with a moderate cha. Chosing half-elf I can get dex 18, int 18, con 16, cha 14 wis 10, str 8. I could get dex 18, int 18 and cha 18 but that will leave me with con 12 which Im not that happy about. As for ASI I need Warcaster, +2 dex and +2 int again but I dont need Mobile because of Rakish Audacity. Fighter 1 dip for Two-Weapon Fighting though? Is it worth is for 4-5 extra damage on the off hand attack, con as saving throw (if dipping level 1) and a few extra HP (HP and Second Wind)? Uncanny dodge and song of defense doesnt synergize at all and most often uncanny dodge seems to be the better of the two.

I dont really know what a good level distibution is here so lets break it up. All builds get expertise, thieves cant, cunning action, fancy footwork and rakish audacity from Swashbuckler and spell book, ritual casting arcane recovery and bladesong from Bladesinger so I will leave those out of the comparison:

SB 3 + BS 13
SB: 2d6 sneak attack
BS: extra attack, song of defense, 7th level spells
ASI: 3 (going SB 4 + BS 13 will net another ASI at the cost of only getting level 6 spells)

SB 5 + BS 11
SB: 3d6 sneak attack, uncanny dodge
BS: extra attack, song of defense, 6th level spells
ASI: 3

SB 7 + BS 9
SB: 4d6 sneak attack, uncanny dodge, expertise, evasion
BS: extra attack, 5th level spells
ASI: 3 (going SB 8 + BS 8 will net another ASI at the cost of only getting level 4 spells)

SB 9 + BS 7
SB: 5d6 sneak attack, uncanny dodge, expertise, evasion, panache
BS: extra attack, 4th level spells
ASI: 3 (going SB 10 + BS 6 will net another ASI at the cost of only getting level 3 spells)

SB 11 + BS 5
SB: 6d6 sneak attack, uncanny dodge, expertise, evasion, panache, reliable talent
BS: 3rd level spells
ASI: 4 (going SB 12 + BS 4 will net another ASI at the cost of only getting level 2 spells)

SB 14 + BS 2
SB: 7d6 sneak attack, uncanny dodge, expertise, evasion, panache, reliable talent, elegant maneuver, blindsense
BS: 1st level spells
ASI: 4

Swashbuckler seems quite front loaded with the higher level archetype features not as great. Panache is okay but with only 14 charisma not reliable (could go 18 cha and con 12 for this build though)) but elegent maneuver seems only good for escaping grapling and a bladesinger should be able to do that with spells anyway. Reliable talent is nice and blindsense very situational.

As for the higher Bladsinger features song of victory is ju​st out of reach and song of defense in itself is nice but uncanny dodge can fill that spot. So going high level Bladesinger is really for the spell casting.

Rogue dip (Arcane Trickster ? + Bladesinger ?)
The other rogue dip Im contemplating is Arcane Trickster as both AT and BS are int based and Trickster counts for 1/3 caster. Thus the logical way to go should be increments of 3 levels in AT. AT 9 nets the macical ambush feature but a dual wielding charcter probably wont spend so much time hiding (using bonus actions to hide). Also you dont get the fancy footwork from Swashbuckler which means Mobile comes into play again as well as 1 level fighter dip. I dactually think a single wielding build is better for AT. I would really like to make dual wielding work now that the GM has made it a more accesible and stronger option but feel free to convince me that single wielding AT + BS is great.

All advice is greatly appreciated!

 

[Rofel Wodring]

With those kinds of stats you may want to consider going Paladin for two levels. Go half-elf, +1 to Dexterity and Intelligence. Constitution gets the 16, Charisma gets the 14, Wisdom the 10, Strength the 8. Of course, you'll need to find a magical item that will boost your strength to drop. If you can't, I recommend still going Half-Elf but going with an 8 Wisdom, 12 Strength and 10+2 Charisma. Do 4 levels of Bladesinger to start with and put a +1 in both Strength and Charisma, then multiclass out. You lose out on hit points, but since you're not going to be wearing heavy armor you don't need to start Paladin and Wisdom and Intelligence as saves will serve you better than Charisma and Strength.

2 levels of Paladin give you a jumble of goodness. You get smite, access to some very good spells, an additional level of spellcasting, a fighting style, and some martial weapon proficiencies. If you're willing to sink in another level, both Oathbreaker and Vengeance give you some very good toys to play with.

Honestly, though, I recommend not multiclassing Bladesinger at all. Additional levels of Bladesinger will just flat-out serve you better than delaying it to pick up other goodies. For example, my AL Bladesinger character has a Flametongue Shortsword. Contingency + Melf's Minute Meteors + Haste gives me a full attack sequence of 13d6+12, average 45.5. At level 14 I can use my Ild rune to enchant a shortsword/scimitar and make that 11d6+36, avg. 74.5. Is an extra 2d6 per round from sneak attack or an extra +4 from the TWF style going to really help me? No. Granted, a lot of games don't have magical items drop at all so the marginal utility of multiclassing isn't as bad, but the equation is mostly the same.