D&D 5E (2014) Bladesinger / Rogue?

[FrogReaver]

How well would going for Bladesinger 6 or 7 then going rogue swashbuckler or arcane trickster work?

 

[Ansel Darach]

You technechily need only BS:3 (mainly for second level spells),

Use Booming blade and take warcaster and sentinel, sentinel wont stop movement when you use booming blade (you use a cantrip rather than an OA).
Booming blade will deal 1d8+mod and 1d8 immediately when they try to move, as they leave your reach you use booming again for another 1d8+mod and 1d8 for movement, and each instance scales at level 5 to 2d8.

Adding in Sneak Attack from say swashbuckler, or just getting to two attacks off then using booming for your reactions may be enough to make it worthwhile overall.