Yeah. While the Complete Book of Elves had some tasty ideas, the mechanics were a bit "out of whack" to put it diplomatically. Whether this newest version is OP, I'll withhold judgement until I can see it for myself.
		
		
	 
I am always confused by this claim; I 
never saw any of the kinds of problems with power in 
The Complete Book of Elves that other people claimed to find in it.
I think the biggest problem that many people had with it, and with the 
Bladesinger in particular, was that they misunderstood how the Kit worked and mistakenly believed that 
Bladesingers were supposed to get a 
massive bonus to their Armor Class 
at all times, rather than getting a fairly good bonus 
only when they were actively casting a spell.  
Normally 
Bladesingers got no bonuses to their AC at all; they only received a bonus to their AC 
while they were actually casting spells, and it was the same bonus that any Fighter got when using the Parry action (half their level +1.)  In other words, 
Bladesingers were able to Parry while they were actively engaged in spellcasting, by executing the 
kata movements and sword forms of the 
Bladesong.  This allowed them to much more safely cast spells in the front line of combat without having to worry about being easily clobbered.  
But, something that most people probably forgot was that during spellcasting you lost 
all other bonuses to AC; no Dexterity bonus or anything like that at all.  So the 
Bladesinger's AC bonus while spellcasting basically only gave them some of the defense back that they lost from their Dexterity bonus, until they got to very high levels.
But I know that 
a lot of DMs mistakenly believed that 
Bladesingers got that AC bonus 
at all times, and so because of that mistake believed that the Kit was vastly overpowered.  I mean, other than the spellcasting AC bonus, 
Bladesingers basically only got +1 to hit and damage with their chosen weapon, and a bonus to hit when making trick-shots which 
only served to negate the penalty for making a trick-shot (this was a running theme with the 
Bladesinger Kit; the 
bonuses they got were mostly in the service of 
removing penalties.)  And all of this was alongside the penalty of 
never being able to have proficiency with any weapon other than their chosen weapon, to the point of losing the Elven bonus with bows and/or the Long and Short Sword (although a 
Bladesinger not choosing either Long or Short Sword as their chosen weapon was kind of a dunce move.)
Sure, if a 
Bladesinger also spent 3 Weapon Proficiency Slots on the 
Bladesong Fighting Style they could also get a switchable floating 2 point bonus to hit or to AC, and if they spent 2 more Weapon Proficiency Slots on the 
Single Weapon Fighting Style they could get an additional 2 point bonus to AC, but that was for the cost of 5 entire Weapon Proficiency Slots (which was something that I 
absolutely loved; allowing Fighters with high Intelligence to gain a real advantage from their smarts, in the form of greater skill from advanced training.)
(As an aside, our DM in our 3rd Edition 
Forgotten Realms campaign, in which I played Gold Elven Bladesinger, actually used the concept of the 
steps of the Bladesong as a dance in a very clever bit of non-combat use of the 
Bladesong; we were on a mission from Evermeet to retrieve an important magic item from an old ruined Elven estate in 
Myth Drannor... an estate which had actually belonged to a branch of my PC's family.  In the sub-levels of the estate we came upon an 
extremely heavily magically trapped hallway, which was floored in tessellated tiles.  In order to pass safely through the hallway one had to step only on certain tiles in a specific pattern.  After our party went through a great deal of investigation and thought, my 
Bladesinger PC was finally able to recognize that the safe path through the hallway was actually the steps of a certain section of a 
Bladesong kata... specifically a 
kata that was used by my PC's family!  My PC was then able to flawlessly execute that section of the 
kata and make his way through the hallway without triggering the magical trap [which we learned later could have vaporized all of us] and with some effort was able to successfully talk the other PCs through the correct steps of the 
kata to get them through the hallway as well (it was only a very small number of steps of the 
Bladesong so it wasn't really revealing any secrets to them to help them make it through the steps just that one time.)  We envisioned the steps of the 
Bladesong as being similar to 
Tai Chi and how 
Tai Chi is taught, which the DM and I had taken classes in together a few years earlier, with the way that 
Tai Chi steps are divided into sections consisting of a number of steps, each section taught separately [the First Third, etc.] until the student is able to master each section of steps until they are eventually able to string them together into a whole.  It was an 
absolutely incredibly cool use of character background, and of using combat skills in a not-combat way, on the part of the DM [but then, he has always been a wonderful DM.])