I assume you're referring to Hirano of "Hellsing" fame? Hmm, I didn't think he was *that* bad when he started out. His style was messy but in a stylish way. Speaking of which, I've lost track of that series...

Yeah, many comic artists really do evolve with respect to their drawing styles over the course of a series and furthermore their career. Then, there are those who don't improve at all but are great storytellers nonetheless. Most examples of this latter type don't get translated into English though, unfortunately.