I doubt that MPEG-LA has any patents on H.265 (they don't have any on H.264). They offer a bulk licensing deal for many different patent owners which is much better than licensing from each individually.
You are right that it is highly doubtful that it would be GPLv3 compatible until the patents have expired. In practice I expect it will be included in FFMPEG and available to open source users even if impure and unavailable to strict Free software purists.
I'm not sure what isn't clean about the H.264 license except for Motorola/Google's legal action that attempts to make the FRAND commitment nearly meaningless. It would be much better for everyone else if they were part of the MPEG-LA offer.
Google signed the MPEG-LA license agreement which would put Motorola's patents into the MPEG-LA pool as well. Arguments are Monday, so one way or another, it will be clarified sooner or later.
Even if they lose that part they won't be signed up to H.265 licence unless they choose to so the FRAND status matters too so can potentially charge excessively. Also if the weak FRAND interpretations stand many other patent holders may stay outside the collective license to get as much as they can.
You are right that it is highly doubtful that it would be GPLv3 compatible until the patents have expired. In practice I expect it will be included in FFMPEG and available to open source users even if impure and unavailable to strict Free software purists.
I'm not sure what isn't clean about the H.264 license except for Motorola/Google's legal action that attempts to make the FRAND commitment nearly meaningless. It would be much better for everyone else if they were part of the MPEG-LA offer.