happy to help :)
personally i think 4op fm provides plenty of possibilities even without the extra waveforms, so the dx11 will be a good move. plus ae and mike p have made plenty of use of em. i think it's right to say that the best waveforms for fm aren't full on saws and squares but more like shaped sines. think rectified, parabolic or half-period sine waves. i assume this is partly why yamaha included them as extra wave shapes and not more traditional ones instead.
also if you can grab one, a yamaha sy77 is a really powerful fm synth from the late 80's that can be picked up for around the same price as a dx7 if you're lucky.
i guess if you had the choice between a dx11 and a dx7 i'd say go for the dx11, but it's a tough call. dx7 would probably be better at pads and being more moody and dark. if the dx11 sounds like my tx81z which it's based off, it'll be very clean and bright compared to the dx7
but a sy77 trumps all, it's debatable if you should just go for fm8 at this point though. not sure of the prices in your area either but good luck!
ps there are a few free sample packs of my tx on my mgf audio bandcamp, check my sig!
Edited by Mesh Gear Fox, 29 October 2014 - 08:02 AM.