I think everyone can and should drive if requested. Usually who creates the group just drives unless he/she can't for some particular reasons (for example I can't stand driving more than 2 climbs in a row, because I just get bored/tired); there are some exceptions to this, but I think I can count on a hand people who always refuse to drive, IF esplicitly requested to do so.
Driving is not even that bad if you actually play the game, because it forces you to play attention on the game: I do a lot more actions when I drive; the problem is that it really forces you to just click and stand on pc, you can't even turn on the light of your room /take a drink without stopping the climb.
Another problem like someone said is bad net: there are some with a clearly faster network than others, someone has frequent drops, etc (I had a lot of d/c last week due to Italy poor connection, and I couldn't really drive since I kept crushing).
Another thing really I can't stand are people who say they can drive but only for half climb: like, why?? I can get that only if you are the only caster and need to heal (tbh there should not be problems with casting/healing/driving, but I get it can get tricky so if you decide to pass the lead that's fine), but monks/ninjas really shouldn't have this problem ^^
fun fact: drivers have less chance to pass master quests
