Koscielny could be a decent player but he's still learning the game.

The problem is rather than learn it in some garbage lower league / smaller club Wenger lets him develop in our first team which is to the expense of our trophy fight. Case in point is the CC final.

Same thing with Fabregas, Diaby, Denilson, Eboue, Flamini, Song, Bendtner, Walcott, Chezza, Fabianski, Clichy etc etc.

He's a good player to have and I think he will become a decent defender but there's no way he should be first choice.