I think a lot of things have contributed to his lack of game time with PSV. Injuries, new country, different style of play, he's still young (and his g/f had a baby when he was 19) so homesickness may have played a part. I do think he would be better at a slightly smaller team than PSV, in Europe, to get more game time - Suarez moved to Groningen before going to Ajax.
I don't know how much of an impact his cruciate injury had when he was 15/16. This put him out the game for quite a while and may have contributed to later problems.
Ultimately, he has all the attributes to be a really good player. And at 21 he can still has the chance of having a good career.