i finally did it.
i beat the SC2 WoL campaign on brutal and fighting air units at the end instead of ground units (and make no mistake, even with "air units" you still get plenty of ground units).
i also chose the opposite of everything i did the previous time, so i had spectres instead of ghosts, mind control tower instead of slowing tower, etc.
my strategy was to bunker and siege tank both sides (like usual). at the artifact i had a fleet of vikings, science vessels, and the 3 BC's you start with. my vikings were completely upgraded (AoE buff and the other thing)
i then used the Hell's Angels mercs to protect the back of my base as well as deal with guardians attacking the bunkers.
towards the very end, my fleet would get overwhelmed by mutas/guardians, and the artifact would be destroyed since the mutas took priority over guardians. so i built 6 bunkers around the artifact and stuffed them with marines.
also, rows and rows of bunkers seem to work well against kerrigan since she has to destroy the bunker first.
when not repairing my base, i was constantly getting upgrades and producing marines from tech-reactored bunkers (one how-to suggested marines/medics, but i found it easier just to use marines towards the end since they died so quickly anyway)
i can rest easy...for now