I just decided a long time ago to let go of any expectations that PbP will move quickly. It's made me much happier in my gaming all around.
My biggest gripe with group initiatives is that it almost completely devalues feats and abilities that improve initiative. As a result of this, it also devalues class and feat abilities that rely on acting before one's opponents. Not a problem for the tanks, but as I much prefer to play light, mobile, fast characters it usually hits me pretty hard.
EDIT: WD's solution takes care of this (I'm pretty sure - but it's too much thinking for me today to actually run it through and see).