Bladesinger with 1 lvl dip in Barbarian?

[RickAllison]

Am I missing something, or is playing a bladesinger with 1 level into barbarian for their Unarmored Defense not amazing?? Youre 1 level behind as a caster and a potential +5 AC.
I made an eladrin bladesinger with incredible rolls, 18s for Int, Dex, and Con, 14 Str
Hes a 4th level caster with melee options and broken armor class of
10+ 4(dex)+ 4(con)+ 4(Int)+ 3(mage armor) = 25 AC!
Oh, and lop Shield on for another +5

It's a great possibility if you have the stats for it, but let's put it in terms of point-buy so it is more appicable to normal games. Let's say gnome so you get +2 Int and +1 Dex. With 15s in Con, Int, and Dex, you end up with 16 Dex, 15 Con, and 17 Int. 1.5 ASI to get 20 Int, 2 to get 20 Dex, leaving a Con of 18. You can't use a shield and get the benefits of Bladesong, so you end up with a character with an AC just over what's possible with Mage Armor and you sacrifice your 20th level feature to do it. You do get Rage, but you have to sacrifice on your three AC scores to make use of it. The build is far too MAD for it to be as good as you hope when you don't roll your borderline impossible scores.

Basically, it's great for you because of your rolls. It is far, far less useful for normal scores. It can seem great to dip into many odd combinations of classes, but many of those have varying abilities that make he build not function as intended.