I'm well aware moonblades have nothing to do with bladesinging but in BG 1 that was about all you could do if you wanted a sword/sorcery combo. Sure you could go Fighter/Mage builds but without most of the later rules to help them out they really suffered.
As far as not being special in its rule incarnations we can agree to disagree. I've played every edition of D&D and there are some points where they have shined. I think they do quite well in 5E if you're not using the point buy system and if you are using it then you have to be much more careful at selecting when to melee mode. Either way with Baldur's Gate being a central point in Forgotten Realms and Bladesingers mostly being found in the Realms I hope they show up, it is just a subclass to wizard and I bet we'll see many subclasses for each class in the game.