I don't think Bentley is good enough. He has shown good glimpses of brilliance but overall he is not consistently good enough. While he has done okay at Blackburn he has not done brilliantly. Pennent is a better player but was a handful. Again he is having some great games but not yet consistent. I think he may prove to be a bigger miss. As for Freddie he did not do too badly in a deeper roll the last couple of games.
I think the difference between Adebayor and Pennant is that Pennant was always trouble even when things went well, whereas Adebayor has been frustrated due to bad managerial decisions and a lack of games. I've noticed AW often goes for players in the Henry/Campbell mould. Players he knows have good relations with their families and eager to help themselves learn aswell as pushing the team as much as possible. Players like Pennant often get self and team mixed up. Perhaps he wants his players to feel a similiar amount of respect shown in father son relatioships. In my life I've noticed (generally speaking of course) that the more determined a sportsman/woman is often determined by having someone 'in their corner' ie a parent. With players that have good role models/mentors there are often less trouble both on and off the pitch. Its not very often you hear of an Arsenal star causing problems for teammates in the dressing room.