I didn't buy Wiig in the role at all
I hated the movie, a lot. I found it unfunny and needlessly degrading to women. I understand the self-deprecating humor and enjoy it, but not to the point where it's downright humiliating commentary.
That said, Wiig is far too attractive for the trainwreck character she was portraying. Anyone else feel this way? There's even a line where Wiig hates another woman for being so skinny, the "joke" being that Wiig is "bigger." Meanwhile Wiig--as we saw in the scenes where she's in her skivvies, is just as skinny if not skinnier!!! Soooo that "joke" didn't work at all.
Is it just further proof that even when the role calls for a softer-bodied woman, the actress must still be waif-thin, jokes be damned?