I can see this being an issue with some, as they actually go for max achievements. Having looked at some, I can see that they would take a great deal of time to accomplish.
But for me, it's the perks. I have few perks compared to most, but I have enough to jump into anything a few times. The thing is, it took me a while to build two of the categories, Fighter and Vehicle, to where they are now. I don't do fighters, just not my thing as I prefer bombers. Vehicles I mess with quite a bit more, but not to the point where I would gain perks at a reasonable rate to justify the use of the heavies on even a light rate. One of the reasons I keep my account active is due to my meager perks I built up in those two categories. Thing is, even if I could keep the account and it's perks/achievements after letting it go inactive, I'd still keep my account active.

So keeping perks would also be a plus.

+1 to OP, regardless.
