My only concern is whether the player loses something of his inner drive once he becomes a bigger fish in a smaller pond. That's not a concern unique to Johnson, more to all players, and probably to all people.
I used to ponder what it was like to be Benteke, or Sakho, Cabeye etc. I'm sure when you are surplus to requirements at Liverpool or PSG or wherever, the idea of leaving so you can play every week is very appealing. Once you've actually signed though, and the dust has settled?
You're at Selhurst on a Tuesday night, plugging away to earn a draw against a club that your old team would have terrified before a ball was even kicked, and then sliced to bits with ease. You would have glided around the pitch, linking up with top class players, being made to look good but also showing you are on their level. Effortless.
That same opposition, however, are not scared of Palace. Everything is harder. Everything must be fought for. You are under pressure for periods. Attacking moves break down. You have to run more. Your old team, meanwhile, are not playing tonight because they've got Juventus or someone tomorrow in the Champions League, in a stadium twice the size of rickety old Selhurst, with a worldwide TV audience as well.
Your career was upwards, from your first club as a kid, to a bigger one, then another, all the time fighting to establish yourself at that new level, doing well, but never able to rest on your laurels, always chasing the dream of playing at the very top. All your graft and focus begins to pay off, you are now being talked about, linked with big clubs. Suddenly your medium sized club wants to make you their best paid player. Its on. Its actually real now. Bids are turned down. They tell you to keep doing the business on the pitch, and it will take care of itself. You perform even better than before. TV people talk about you. Then one is accepted, a nervous wait ensues, then the deal is done. Everything has led to this moment.
Then bit by bit, it all turns sour. The big club have lots of other options, you are not certain to play. They don't need you. They are happy to accept a bid for you. Most players only get one chance at this level. You didn't quite make it. How does that feel?
Your wages stay similar when you move to Palace, but they cannot afford to leave you out of the team having made such an investment in you. They certainly can't sell you on for the same money they paid. You can have an off night and probably still play next time. You can give 80 percent of you, and its no worse than 100 percent of the guy next to you in the team.
You once scored a late winner in front of the Kop. Now you are struggling to get a chance in front of something called the Whitehorse Lane end. Then someone catches you late on the ankle...
Perhaps Johnson is young enough that he feels he can score 20 goals a year for us for three years and get back to a Champions League club? Perhaps he's right. Its still a big old comedown to navigate.
Buying younger players from the championship is not only better in terms of value, they and us are a better fit in terms of stage of career and upwards momentum. Johnson would have to overcome some emotional gravity. Not sure if I could.