my opinion on the situation:

i think its fine you got a long cage derailleur, especially if youre runnning a triple. also, the problems you describe are not the fault of the rear derailleur, but of the shifters (both right and left). the derailleur is just three springs and some pivots, while the shifters consist of dozens of tiny plastic pieces and are much more likely to be at fault. i have also found that lower end shifters/brake levers (especially campy) are very finicky, and may take a while to perform up to snuff.

"So when I've downshifted all the way, and then try to upshift, the pawl skips the first engagement point and then just slides across the smooth portion on the engagement ring." this just sounds like your cable is way too loose.

furthermore, your poor shifting can be a result of your housing being too long or too short. take a look at that.

in summary:
- its not the derailleurs fault
- tighten the cable! downshift all the way. upshift one click, and while pedaling, tighten the cable with the barrel adjuster until the chain jumps up to the next cog.
- check your housing, it may need a length check.
- break the shifters in a little