I think thick, if done right, can make for an exceptional blade.
The thickest knife I own is the Regulator, at a third of an inch thick.
It is an AWESOME knife. With the full flat grind, it is one of the best splitting wedges I've seen for batoning a log, and with the tapered tip, it has a very strong point that still penetrates exceedingly well. That means, for digging a hole, or drilling, or prying fatwood out of a stump, the regulator is just plain awesome.
It is a thick knife, and sure isn't a slicer, but it doesn't FEEL like a thick knife when you're using it. It has the thickness where it counts, and takes advantage of it.
I wish I could say the same about all of the fat Bussekin knives I've held or used.