My feeling from watching him play is that his play has become more conservative (too conservative for my taste).
The changes feel very "by the numbers" to me. He is backhand flicking returns a lot less now, opting to short push an absurd amount. He almost never runs around the forehand to flick receive the serve from the forehand side now.
In general, he barely ever tries to seize the attack with over the table play anymore, opting for short pushes instead.
Even when looping close to the table, he seems to be trying to control the point through placement and consistency rather than the raw power he used to generate.
And up until the Swedish open, he seemed also to be very forehand dominant from a bit further back behind the table.
In general, there seems to be some good reasoning behind these changes, he has cut out some riskier, more error prone parts of the game for lower risk, more consistent alternatives, the forehand is inherently stronger from behind the table, and flick returns don't quite finish the point as much as they used to. But the sum total of these changes seem to result in a philosophy of play that is just... worse, so conservative as to not fit into the modern game anymore. IMO he needs to just take those risks and accept that sometimes there will be errors, accept that his opponents might return his flicks and have the confidence that he will be able to return that even harder.
I don't know why he's changed his whole philosophy of play, whether it's loss of motivation, or just because he wanted to improve his control game to beat Ma Long, and just kept going. But it's really not working out for him.
He plays like FZD trying to play like Ma Long now, and he just doesn't have the same feel for that style of game. He's better off playing like FZD just trying to play like FZD.