I hadn't seen anything on Remy's character - I am guessing here - big headed type?
I do recall reading that he seemed to lose interest at Newcastle (with the rest of the ship in similar mode)
Dude, this is just my impression, so more than likely I'm being unfair. He missed the game against us last game of the season. According to Pardew, both at the time and since, he was deemed not to have been quite fit enough. He'd had the calf injury March to April, which was apparently a re-occurrence from the beginning of the season, and had missed training all week in the week leading up to our game, again with a calf problem, so Pardew deemed him unfit, and that was the story given to the media.
Remy and his representatives, on more than one occasion came out and denied this and stated he'd come to an arrangement with Pardew to be rested so he'd be fit for the World Cup.
Whether he was injured or rested for the WC, in resting him Pardew did the player a huge favour and the club and fans a disservice, and therefore Remy should have accepted the public reasons given and backed his manager in return for being rested. If he was rested, Remy knows the manager can't admit to that, as it would cause disharmony amongst the players and anger amongst the fans.
Asking to be rested for the WC was a selfish thing to do (if that's what happened) putting himself (Remy) before the club paying his wages.
Telling the world he'd been rested 'as agreed' put his manager in a terrible situation, showed no respect to the fans and highlighted how he'd put himself and his WC place ahead of the club and fans.
There was a similar incident at Marseille, I think it was surrounding the medical, which his people denied there was any problem, which we know wasn't true as that's when the heart condition was discovered.
Also look at his career in England. He signs permanently, not on loan, with a relegation threatened QPR in the January, who then get relegated. He has a release clause to avoid being stuck with the team he chose to sign for. He gets his wish not to have and to try and help QPR get promoted and playing in the Championship, by getting the loan move to Newcastle. Despite Newcastle giving him the opportunity to remain in the PL, he has no desire to move there, and as you say, hardly broke his neck trying for the club in the second half of the season. Now QPR are back up, the club that gave him the chance to play PL football, he's still not interested in playing for them, or Newcastle the club that gave him the chance to avoid the Championship, and both clubs have bent over backwards, arguably to their cost, to accommodate the player's wishes.
There was another incident at Newcastle and at Marseille though I can't remember enough details, but the things I've read since the failed transfer, have just left the impression of a selfish and rather ungrateful individual. As I said at the start, it's only my impression and interpretation of things I've read, so it may well be my impression is based on inaccuracies.