I don't think Bolton's relegation is all down to Coyle, they should have stayed up for the incompetent Chris Foy. A big part of why they ended up going down was that Coyle changed the philosophy from the big and combative longball merchants that they were to more of a passing side; they still got it up to Davies to battle just they were n't so one dimensional and direct as before. The change of style initially worked however players like Johan Elmander and Gary Cahill were n't replaced adequately if at all and the latter was poor in the months prior to his departure and players like Holden and Chung-Yong Lee were out for long periods with injury and if Bolton got their money out it was only to sign championship players or MLS imports.
The club that Owen Coyle took over was ripe for relegation, the mismanagement and debts lingering smell in the room, OC came in spayed some air freshener cleaned up the place and began re-decorating the place but it was all in vain the smell would n't go away forever the debts and the cost cutting dragged them down just as it did at City and countless other clubs.
Owen coyle's vision may have worked under more productive circumstances however ultimately it was the wrong club for him, although at the time he was the right manager for Bolton as when jumped ship from Burnley there was only 2 relegation places to fill. Bolton did well to appoint him at the time they got another 2 years in the premier league and had they gone down in 2010 they probably would have ended up in a much poorer state, it was a somewhat cynical act to employ him just as it was of Aston Villa to appoint Lambert from Norwich, displacing their struggles on other clubs.