Play testing is the most important part of game development. Indies who struggle to come up with concepts are really sleeping on this. If you run play tests well enough your roadmap will almost write itself. Players will do and ask for things that you would never dream of.

I think an intense culture of playtesting is why valve software puts out games so rarely. Their new strategy seems to be to keep a title semi-secret for years while a small army plays it full time. If Deadlock makes it to market, it is almost certainly going to be an acceptable game to most who are even remotely interested in the genre.