Gotten close? Either you backflip - or you don't. If you're "close" to a backflip with a Phantom I guess that would mean that you smashed it head first into the ground. Just my opinion on backflips after years of gymnasticsI've gotten close a few times and it's a little scary but kinda awesome.
I WISH the Phantom 3 could do flips successfully. I have used a smaller, low-quality acrobatic drone with horrible 720p to get shots that I needed like faking parkour and kungfu moves. Found it to be the safest and easiest way to fake a backflip off a building or someone getting shot mid-jump (and flipping backward). It is a very niche need, but would be nice to have as an addon or option in the SDK.