In terms of force use, Yoda was always as strong as he needed to be to for his writers to make the main characters looks like chumps (Obi-Wan and Anakin vs Tyrannous, various Jedi vs Sideous). As far as consistently displayed power the writers seemed to like to have him as a ham-fisted deus ex machina.
In terms of quality of leadership, well he was probably one of the most awful beings to ever govern any body, military or political. I think a large part of that is tied in with how he was the canon's DM-hammer, but still, throughout the prequels and clone wars he makes some of the worst decisions possible and was likely one of the main reasons Sideous was able to play his game long enough to win.
In defense of his clone-wars decisions, however, the writers were forced to sandwich their writing into GL's abominable storytelling so they probably did not have much to work with in terms of making Yoda less of a simpleton tool.