I absolutely love Bladesingers. I played my first Bladesinger PC back in '93 using the original 2nd Edition Fighter/Mage Kit, a Grey Elf from Celene in a Greyhawk campaign (I hate this modern assumption that Bladesingers are a specialty 'Realmsian thing; the CBoE was a general D&D sourcebook) whom I got up to the maximum levels for an Elf PC of his ability scores (Fighter 13/Mage 19.)
I later played a Gold Elf Bladesinger from Evermeet in a 3rd Edition/v3.5 Forgotten Realms campaign 16 years ago, and got him to 19th level (Fighter 4/Wizard 2/Bladesinger 10/Eldritch Knight 3.)
My current PC is now a 4th level Grey Elven Wizard of the Bladesinger Arcane Tradition in a campaign set in my brother's homebrew campaign setting.
I play them so infrequently even though I love them so much, because I love them so much, and I do not wish to have their specialness be diluted through overuse; I therefore reserve playing them for special occasions in campaigns with just the right conditions and flavor. No one else in our group has ever played one (although my brother would very much like to some day.)
And I very, very, intensely despise the idea of non-Elves being able to become Bladesingers.
Bladesingers were originally described in The Complete Book of Elves as champions of the Elven People, who practice a special, uniquely Elven, magically enhanced martial art, and this martial art was a closely guarded secret that was never taught to non-Elves (not even to revered Half-Elves) and altering these important details so as to allow non-Elves to become Bladesingers only serves to dilute its specialness and rarity, and renders this unique aspect of Elven culture that much more mundane and ordinary (which is yet another part of the ongoing trend of rendering rare and special things into commonplace and ordinary mundanities; if every other person in the world can do something that is supposed to be incredibly difficult, rare, and special, then there is no longer anything at all special about it, and its supposed difficulty is turned into nothing but a joke.)
The reason why the Bladesong was restricted to only Elves was for both cultural and for very practical reasons; it took decades to learn to do it, so that by the time a Human had managed to learn the steps he would be far too old to do anything with it. Also because Bladesinging requires the Elves special connection to magic and magical senses, which are a necessary part of the martial art, the Elf extending his senses out through the magic surrounding him.
I despised it in 3rd Edition when they opened it to Half-Elves (The Complete Book of Elves made it very clear that no non-Elf was ever taught the Bladesong) and if it is indeed true that they have now opened it up to any race then I despise this retcon even more.
If they want to have a subclass for melee-oriented Wizards then they can make a general Battle-Wizard Arcane Tradition; they could even use similar game mechanics as the Bladesinger! But the actual position and title of Bladesinger is a uniquely Elven cultural tradition (the champions of the Elven People, for Goodness sake!) and opening it up to just anyone is actually insulting to those of us who love the idea and concept of Bladesingers as more than just a mere collection of game mechanics.