Firstly Arsenal did offer new contracts, again Bendtner has been trying to force a move for 3-4 years and it is Arsenal/Wenger, not Bendtner that is stopping him moving on. You can't "show the door" to someone that has been desperate to leave but you've forced to stay, it's the opposite of showing someone the door.
Second, use proper stats
http://espnfc.com/player/_/id/71647/nicklas-bendtner?cc=5739
In 08-09 he started 17 league games, got 9 goals and 2 assists in 69 shots. FAC 3 starts 2 goals 1 assist. CC 2 starts 2 goals 1 assist. Denmark 4 starts 2 goals 5 assists.
His best season was 09/10 when RVP was injured and Bendtner had his FIRST sustained run in the team mostly after xmas. He started 13 games, got 6 goals, 5 assists. In the champs league he started 5 games, scored 5, got 1 assist, in 14 shots.
The vast majority of the time at Arsenal Wenger consistently dropped him even after great performances.
He absolutely doesn't have no composure infront of goal, that is just shockingly daft thing to say. he's had bad games, so has Messi, Ronaldo, Suarez, RVP and Henry.
He has been consistently played out of position, rarely had run in the team, and when he's had a run he's provided goals and assists and against all competition. Across 2 years of games against Barcelona he was easily our most effective player.
No striker plays brilliantly and scores loads when the majority of their appearances are 5-20 mins at the end of games where the team is winding down. All strikers do better with a consistent and long run of games.
Some of the competition he's played in Carling/FA cup is crap, some has been decent. His scoring rate on those competitions and for Denmark have been very very good. He was excellent in the last Euro's.
Considering in any spell he started a significant number of games he scored and assisted well, his stats are very good. His performances are mostly effective and good. He's great at defensive and offensive set pieces. This year he still has 2 goals with only one start in the league AND we've scored I believe 2 or 3 goals after he's come on from set pieces. Mert being the only target in the box, Bendtner comes on and suddenly we looked effective from set pieces the second we had two guys moving well in the box.