It must be said that Donovan is not nearly as dynamic as he was just a year or two ago, and he is quite a long way off where he was in his mid-twenties. Some might say this goes without saying at his age but what is not being stressed is the steepness of his decline. He seems to have lost a lot of pace this year- particularly in the latter half of the current MLS season. He has struggled with injuries this year- and perhaps it is simply down to that- but combined with the apathy he has been displaying in interviews, it seems tied to something more endemic to his feelings of the game and diminishing physical skills.
Some may argue that his stats are as good as ever, but these are somewhat deceiving- he is not a player who can take over a match anymore.
While he has other tools in his locker it was really the combination of those- vision/awareness, passing range, combination play- with his pace that truly made him stand out. Those things are still there but he rarely, if ever, attempts to take players on anymore. While this reluctance is ok in MLS where his other intangibles make up for it, I can't see it working if he's played on the wing in the Premiership.
The key really is if it is all down to injuries this year. If so then he may get back that quickness he used to have in abundance, and with it some motivation to play, but the odds of that seem slim to nil.
That being said, he has always been underrated for not playing in a better league, but those in the know appreciate how much natural ability and talent he had (and may still have). By far the best U.S. player of all time and tbh Everton only got a taste of what he was capable of.