Small frames are a pain in the arse for cyclocross as it makes it way more awkward to shoulder the bike without cracking your elbow on the chainring.
My own "traditional" size is 58/60 cm c-t-t, but 57cm is not problem at all.
55cm is also fine, but 50cm (I also tried that for a whole season) is a bit problematic.
But: there are hardly any races, where you have to shoulder your bike, so what are we talking about?
If i try and shoulder my compact it's a nightmare, but my non compact cross bike was fine.
You obviously just have shit elbows.