Well, I think Kirk was arguably the right man for his time; one of the things that stands out to me in TOS series is that it seems like a more militarized situation, and maybe an aggressive, tough posture was the right one for Starfleet at the time. The progression is one of the things I love about Star Trek. There's a kind of development. If we're going to get all meta about it, we can talk about how Roddenberry's sensibilities evolved as he became an older man, but I think it's more fun and more interesting to take the text as a whole (for a philosophical justification see, 'The Intentionalist's Fallacy'), and I would like to say, while I consider Picard to be the best Captain (favorite Captain, I'd be divided between Picard and Kirk), perhaps the more revealing question is who was the worst Captain within the context of his/her circumstances. I'd cast my vote for Janeway. I would be inclined to argue that Janeway's alliance with the Borg was not only morally inexcusable, it's probably the only case where a Captain's decision was clearly disadvantageous to the progress of Starfleet. As a side note, I never saw a Captain make a more immediately morally horrifying decision (Archer's bullshit in the Congenitor episode takes second place) than the murder of Tuvix, but I give props to Kate Mulgrew whose performance in the series I consider to be fantastic.