I was kind of the same. From the beginning I was skeptical but I think he has proven himself to be good. Now lets see how he performs the whole season and hopefully he doesn't do an Amauri, great the first 6 months and then it all went fucking nowhere.
I see your point and I agree with most of it, but lets not forget that Quags is primarily a seconda punta, so he doesnt have to be exptected to score a goal every game (or two) like Amauri (ROFL) or the Yak.
He just needs to keep doing what he's basically done for all the teams he's played for in the past few seasons...work hard, score screamers, set up the main ST and continually get into good/dangerous positions in the opponents area.
Anyway, he's a definite signing for next season.