I have Gargoyle in my WDR4300 and:

Yes gargoyle, openwrt and dd-wrt are very interesting, had them on my 1043nd. But they all lack some wifi problems that block out devices like printservers, webradios, some mobile phones and denon ceol hifi devices. Bug reports are slumbering forever, while same router with tp-link firmware works pretty well.

The 3600 need a simple URL: line to update every possible dydns service by setting the right url. So i hope the tp-link support read this too. Please update this in former firmware releases.

Tuxnet-HH

This is only my suggestion, I'm very happy from this firmware. We must wait for new solutions in original firmware.