I think I'd go for Edward on both the character and the gameplay fronts, though I think Evastio makes some good arguments for Cecil. One of the criticisms I've heard of Cecil on more than one occasion is that he's a bit bland and one dimensional compared to Kain, but I think that's quite an oversimplification of things, which I think your post does a lot to dispel.

As for why I think Edward, I think in gameplay terms there's the temptation just to see him as a bard that you want to have use Hide whenever you're forced to use him in battle, but he does have a positive contribution to make in battle. In character terms, he has to deal with quite a lot, especially considering his doesn't really want to be in charge of Damcyan. However, I think the strength of character he develops and shows actually make him a more impressive character than people often think he is.