1 - No thanks, I like playing with my friends in Crystal. Limiting this will be the final nail for me on this game.
2 - Probably the best option
3 - Also a pretty good option. Could always just give a unique buff like "DMG increased in certain instances" or I don't know. Keep the buff data center-wide until a certain consistent player threshold is reached.
4 - Yeah I want to keep my houses I've decorated, so that's a no from me. Maybe if this system was instanced...

I understand Dynamis' problems, and frankly this is on Square's shoulders, but there is no incentive of playing here in the first place. Only time I've seen activity is with Hunt Trains from other DCs coming in for ours and then leaving right after.

We need a carrot, not a stick.