Not saying I had the same degree of injury as Froome had (not close fortunately) but I also had a pretty severe leg and knee injury some years ago which required two operations and a cast for 6 weeks and clutches for 10 more. Cycling was a part of recovery that was required from me by my physio, so I did that a lot (would have done it anyway though). I certainly struggled a lot the whole year with power output on my injured leg and it was even rather noticeable the next year (visually and performance wise). Then it evened out. No problems today (at least in terms of cycling).
Still I think, that Froome will not improve much. He had now focused solely on recovery and getting back in shape for almost two years with probably the best support one could think of. I am just not seeing it. At all. A bit of a shame, I agree. Never liked him (or actually actively rooted against him, tbh) but would of course now like one last big victory for him, seeing how he struggles. But in my book he is farther away from that than in 2011 before his transformation.