There are compact frames, and compact cranks.

A compact frame uses a shorter seat tube and an upwards sloping top tube to get the same fit as a traditional geometry frame. A compact frame is lighter and stiffer (although this advantage is to a large extent negated on a complete bike because you need much more length of unsupported seat post) than an equivalent frame with traditional geometry. Also, there's more standover height so each size can be made to fit more riders so manufacturers don't need to make as many sizes.

Compact cranks have become fashionable with roadies looking for lower gearing but are too vain to use a triple. It's "compact" because it is able to fit smaller chainrings for lower gearing. It's lighter than a triple, but it doesn't offer the selection of gearing that a triple does. Also, I've found that I tend to get a "hole" in the middle of the gearing that has me switching the front back and forth quite a bit more than I'd like.

The original tri-cross only came with a compact double and that may be what you saw the complaints about. It sounds like you're looking at the model that comes with a triple so that shouldn't be a problem. Don't worry about compact frame geometry either. Good frames can be made either traditionally or compact. If it fits, it'll be fine.