When wisdom comes around, people had better take notice. Carly's post is excellent. Sluggers.
Pitches get reputations as "gimmicks" when there are a whole bunch of pitchers around who don't throw them well. Sure, a drop curve is a poorly thrown drop if you can't throw either of them right, just like any other movement pitch is just a really terrible slow fastball if you don't throw it right. If you CAN truly command a pitch, it's a different story.
I don't usually teach the drop curve as its own pitch unless I see that it would benefit a pitcher. I had one pitcher whose only two movement pitches were the drop and the drop curve. They were distinctly different and both very nasty. We moved to the drop curve when she couldn't get the regular curve; her hand just didn't want to do anything but turn over hard.