I'm factoring in his age as well though, I mean he is not going to be a prime Zlatan coming to the PL. Unless he is some freak of nature which I don't know about.
Like I mentioned to Steve and Mike, this move may very well work out but the implications if it doesn't may be more costly than you think.
Every move is a gamble, even the players at good age and playing in same league are gamble as they might not step up to the level needed.
Likewise Ibra is a gamble but the one we should be taking. He is 35 but scoring for fun. He is incredibly strong player and for a player of his size, his technical ability is just amazing. He lacks pace but again, he has very good game intelligence and playmaking skills. It's very hard to disposes him.
For a year or 2, it's a gamble worth taking.