I have used an alternate code pack over the years:
http://shark007.net/advanced.html. You can read on his page why it is to be preferred.
The problems seems to be that some codec packs cause conflicts with existing codecs and/or that some software installs their own and mess everything up. Sharky claims to fix that by in addition to installing codecs also doing a cleanup.
As to image sequences for Diffuse maps: this has been requested for iClone quite some time ago, probably before the Feedback Tracker was introduced. As yet no dice, so maybe time to revisit.
As many here, I only render in image sequences out of iClone, so no codec hassle there.