it is incorrect form...it's understandable if you have shorter arms but the problem is your marker is now raised...either way you will still have a Z shaped arm, and it would cock your wrist backwards

look at that picture, notice his wrist. not only would that be uncomfortable but he would be shooting slower as well. Your muscles pull each other and that goes from the digits to the carpals to the fore-arm. Now cocking the carpals back, the muscles and tendons to help the digits aren't relaxed enough to help speed the movement of the fingers.
now compare that picture to nicky cuba

look at how much more relaxed his arm/wrist is. The fingers will the get the support from the other muscles help pull the trigger.
ever wondered why pro paintballers don't use drops? well there ya go
think about it like buying new shocks for your car that aren't race quality...They ruin your car because you're overlowering the car so you lose handleing...so your paying money to lose performance
edit- more reasons
Drops do allow you to hold the marker closer to your body and this can help you play tighter but they have some cons:
1)They make the marker taller. If you shoot with your marker strait up and down and not tilted to the side to hide your hopper behind a bunker this means the hopper is higher in the air and therefore harder to keep in cover, therefore more likely to be shot. If you shoot your marker tilted to the side you'll notice the extra height raises the center of gravity of the marker. Also because it is taller it is more difficult to sight down your barrel and you'll have to keep your head up rather than tuck your chin in. Throat protecters became widely available at paintball stores around the time that drops were envogue...just realized that now.
2)They may throw your marker off balance depending on the marker and size of drop. Most markers are balanced just behind the trigger when you throw on a tank and a hopper. A drop will bring a lot of the weight from the tank forward. So when your running, diving, getting lit up or whatever distracts you from handling your marker it may fall out of your hand easier. Reloading while shooting may also be more difficult. But smaller drops combined with larger capacity tanks will actually put the marker back in balance.
3)They add weight. And you know paintballer's won't stop demanding weight reduction until their $1,200 set ups can actually be lost in a gust of wind.
4)Bad hand positioning. Ideally you want to be able to fit your wrist in the space between the tank and the grip. This keeps your forearm from having to wrap around the tank thus providing a larger target for the opposition. A drop makes this impossible. The reason why so many people are going for the ASA/rail set up is because both the ASA's and the tank regulators are getting smaller and smaller. The rail helps create some space inbetween the tank and grip.
5)Looks. Some people just don't like them. One of the things that really killed the drop was the styles companies came out with just as players were realizing all these cons. They had all of these fancy milled designs in the shape of flames and sharks and all kinds of unnessessary crap. But now that I think about it...a direct mount milled to look like a spider holding your tank in place would be pretty sweet. The abdomen or head could be the on/off knob