-Release the big rule book as it is now, and keep it updated via the internet via FAQs and clarifications. Particularly silly/poorly worded rules could be straight re-written.
-Release the codex as they are now, and after 6ish months release them online with the FAQ and integrated rule changes.
-Use the internet to update terrible units. Lets face it, 5+ years between codex updates is stupid. Some units just suck and probably hurt sales for the models. Pyrovores, Carnifexes, Tyranid Warriors, Whirlwinds, Scout bikes, Noise marines, Raptors, Tactical terminators, Blood Claws, Chaplains, Captains, Swooping Hawks, Mandrakes...etc. Every codex has a handful of units that are either straight bad, or pale in comparison to it's other units that almost never see play. GW could boost sales for these poor units by bringing them into line via web updates. Some units beg for even the tiniest update or tweak they would make them better. This doesn't even have to be all upwards, there's a ton of stuff that needs to be made worse; Hive Guard, Grey Hunters, Psy-bolt ammo for GK dreads, Vanilla assault termies, chimeras...etc.