Most of the greats and most of the great hip-hop songs from way back when were pretty much based on loops. In a way I can see how it was more of a skill back then considering the technology. Getting a sample to loop with an SP-1200 must have been a pain. DJ's must have spent hours on the decks juggling beats and looping records. Today, since the technology has developed so much and made certain things alot easier, it creates a demand for beatmakers and electronic musicians to be more creative in the use of the improved technology. But when it comes down to it: if it sounds good, it sounds good. Nonetheless I don't think you should feel discouraged to be bound just by looping, try pushing out of those boundaries even if it does sound like crap. It'll help you become more creative in terms of your techniques and use of the technology. A good loop is nice, but chopping and trying other things allows you to become better at manipulating the sample to sound different and possibly better (for your beat that is).
I suck at chopping also. My better beats are usually based on loops too. But I still try to chop to look for sounds that can be manipulated re-arranged or emphasized, you never know what you'll find.
It doesn't make you any less of a beatmaker but I think you end up limiting your skills and creativity in the long run by bounding yourself. If you're going to loop I say try to at least dig for some rare and unusual grooves (probably impossible to do these days) that are unheard of or possibly never used before. I think listening and finding a loop on a record is a skill on its own. I think you should (if you aren't already) also try to add instruments to the loop just to add to the creativity and textures of whatever loop you use: Drum hits of course, synth section, strings, stabs, overdubs of live sounds, etc. Get creative.