Like this. It works for buying bases and getting quests that demand more than one people. It's enough that the char is ingame, even if it's logged off. Anything that requires multiple players to do is completely doable alone with alts and alts/multilog/proxies. If you make it impossible for logged off chars to count in the char check, players will use dual log. If you disallow dual log, players will use proxy. If you put skill requirements, players will bring their alts, duh
The "need multiple chars to do this" just aint working. It's bypassable by loopholes and those who refuse to use loopholes get annoyed and demand justice.
Players like challenge and overcoming challenges. However if challenges are set in ways that demand loophole methods to bypass, they will do it. This is why challenges need to be set so that one can overcome them by fair and square skilled gameplay and cheating has no effect.
Features like that should simply have the difficulty setting put in such magnitude that even multiboxer can't compete. TC is good example of succesful teamwork requiring quest: you can't defeat multiple players with multibox. This can be withnessed in one of Res' videos where he smashes some BHH proxies.
Turn based pve is another pretty decent one. Skilled use of terrain and knowing the ai reactions to your movement awards rewards. Surely there are ways to abuse the ai but so far fair tb fight is okay too, at least for me.
