The point is: It should be a viable alternative to the robe-wearing wizard, simply because some like the concept of fighter-mage or a more martial mage (Gandalf comes to my mind), these guys will need more armour - if they give something up in return, I'm fine with it. Additionally, it makes a wizard/whatever-multiclass easier... and more options are always fine, as long as one option doesn't outshine all other options.
If wizards in armour don't give something up (like feats, because they need to burn them on armour) and the armour-wearing wizard becomes the "best" wizard (i.e. a no-brainer), well then I'd also be very discontent.
Cheers, LT.