There's nothign you can really plan for this in any way, unless you want to establish certain baseline rules for the game. If your players have the ability and the inclination to play this campaign, establishing any sort of hard mechanics will only be a needless obstacle to the progress of the game. If they have the inclination but lack the ability, mechanics won't help as you'll basically be doing everything yourself, with them steering in only the most vague sense, making a futile and pointless campaign. If they have the ability but lack the inclination they'll have no fun and not meaningfully participate.
The best part of players play RPGs for combat, with everything else being an interesting decoration or break. Introducing a game that isn't fundamentally based on set rules for combat as its core element will be an interesting but confusing novelty at best and a tedious disaster at worst. Players that are used to narrativistic games where the mechanics of combat are less important than world-simulation and fighting things is nothing more than one potential solution to the few situations where it is appropriate will adjust very well to this. As always, good GMing is about knowing your players.