Tower Defense is kind of old and overdone. It seems like their quality gets less and less as time goes on. I prefer AoS, but given how high quality many have been in the past, unless you can put forth the effort and try to match those- its pointless. Altered melee is too easy to do, since 90% of everyone just uses ripped blizz maps with a few minor object editor changes. A really good hero seige, however, is really needed. Try working on one of those.
-VGSatomi