FormerlyHemlock
Hero
As far as Bladesinger goes (since this is the subject) it looks like a fun class. It sits on one end of the spectrum of gish with Eldritch Knight on the other. It seems to fit more on the "fun" than "power" side of being a caster and will probably appeal more there. Kind of odd that the best cantrips for become less useful at 6th. Starts off a bit more survivable at lower levels than a lot of the other Wizard classes. A friend of mine complains that it would be good if it allowed GWF or PAM with it since to him that is the only type of melee.
Let me remark in passing that Rogue 2/Bladesinger X is a fantastically fun multiclass combination. It makes good use of the Bladesinger's Extra Attack feature (which would otherwise be a bit of a waste) because now you can cheaply grapple/prone enemies. You can even Enlarge yourself to grapple Huge enemies with a high success rate (e.g. a Str 10 Rogue 2/Bladesinger 10 with Athletics Expertise and two attacks has a 90% chance to grapple an Adult Red Dragon, and a 48% chance to grapple AND prone it), and then the Bladesinging bonus helps you keep your concentration if the enemy damages you. (BTW, prone Adult Red Dragon vs. AC 21 Bladesinger has only a 20% chance per attack to beat the Bladesinger's Shield spell--although the Wing Attack legendary action will almost certainly succeed in damaging the Bladesinger once per round.)
This is one respect in which Bladesingers have a definite edge over Bladelocks, since Bladelocks don't actually have Extra Attack and therefore cannot make multiple grapple/push attempts per turn.