You are correct, it doesn't matter whether you game plan before or after the midweek, the midweek just gives you an opportunity to sign players between games.
I'm toying around with the idea of having some leagues sim more quickly - probably every 12 hours instead of every 24 kind of a thing - but I don't think I'll remove midweeks altogether because if you have some injury issues you could get into a bind since there would be no way to sign players and then place them into your depth chart without a midweek sim.