Unless something drastic happens, Kagami will remain my favourite.
It actually makes sense for Tsukasa to feature prominently. The main dynamic pairing in Lucky Star is that of Konata and Kagami, and where there is Kagami, her twin sister, Tsukasa, naturally follows. It is a package deal.
Miyuki suffers because she is an entirely separate package.
[Wry]
Maybe they will do another change of director, and shift the focus onto Miyuki.
[/Wry]
Cheers.