Optimistic at this point. Sure there are doubts, just as there are about players coming back from Achilles injuries and the like. Nowadays one must be cautious about being optimistic about a player who has had a few concussions. The hang-up, I think, is the fact Jaylon was and possibly is on the cusp of being permanently limited. But that's more common with football injuries than is obvious. In the football world, virtually every surgery is deemed a "success," but some are more dicey than others. I've never been too concerned with the idea that others haven't come back from his injury at their previous skill level. Medical advances have been exponential. I remember when players rarely returned from ACL surgeries at their previous skill level, and when there was no such thing as Tommy John surgery. Given the marvels of medicine, it's difficult to compare the past to the present.
I don't think anyone knows the extent to which Jaylon will recover. And the idea of players being, say, 80% or 90% of whatever percent is odd. How would one measure the percentage? The bottom line is there is plenty of room for optimism, and as a fan, I don't find it difficult to choose that path. What is the good of being a fan if I torture myself with what-ifs? I can spend plenty of time doing that in my day-to-day life. That said I don't think this is unreasonable optimism. Contrary to what some have said, the Cowboys have released quite a lot about Jaylon's recovery, and for several months now it has been quite positive.
We'll all find out. Play ball.