Well, I'm sure I'll be attacked for this, but I'm gonna say it anyway:
Tiny harddrive, barely enough RAM (and not upgradable to the "enough" level), no dedicated graphics, only dual-core processors. It certainly isn't bad, but Apple just took the "pro" out of the 13" line. And come on - it's freaking expensive. If you upgrade the SSD to 512gb and get an i7 (still dual-core - WTF?) processor, it's only 99$ cheaper than the mid-level 15" rMBP, which packs a heck of a lot more power. What gives???
the 13" is NOT a pro device in my opinion. It's more like a beefed-up and slightly heavier Macbook Air. For that, it just costs way too much.