suggestions

I was thinking of a few platinum (or various other trophies - could be silver, gold, bronze)

One time unlock-able trophies such as:

Log off time 6 months + Log off time 1 year+ Log off time 2 year+

In other games there is a reward system for you coming back into the game after an extreme time of inactivity. A single platinum trophy isn't game breaking - but it is a nice reward, a little cherry. Everyone loves little cherries. Except Hitler, but that guy fing sucked.

Hmm, not sure. I don't really think a plat would affect someones decision to come back, like, at all. Platinums (and other trophies) should be achievements, not an incentive to play the game.

I would see that more along the lines as an incentive to not play, and then play again, like a rehab failure trophy rofl.

"Disincentive rehab failure trophy" is a good way of putting it.

I've seen the systems that try to lure players back with goodies like this, but that usually involves emailing them or something, trying to entice them back, and I don't do (or plan to do) anything like that, so I don't see this really have much effect.