The Muslim community has definitely been stepping up to denounce these attacks as they should, but I believe they should take it further. Not just denounce it, but march and call out to all real Muslims to be extra vigilant of those that may be possible extremists. Keep an eye out for anyone they know in their community that has a recent behavior change, especially those that went back to the Middle East and returned, then become more distant and closed in.
The Muslims understand their own much better than we do since most non-Muslim Americans' understanding comes from TV these days and we all know that is not the best source for facts. Be loud, show that the real Muslims do not accept the extremists, that the extremists are not real Muslims but a bunch of murdering psychopaths. It will be harder to terrorists to infiltrate if they know their neighbors are actively keeping watch.
I wouldn't call it a reformation of Islam, I'm sure that 99% of Muslims do not believe in the archaic version of their religion, at least those in the US. They just need to be more vocal and upfront about it.