Display MoreSkill reset needs to be obtainable in game through reasonable. The amount of effort required its debatable, however the success of this server depends on the size of the player base, and not just the ones that donate.
I have very little issue spending $5~ a month to support the server, my friends, however are a bit more stingy and might not feel so inclined. They might show their support in different ways, like getting more people to play (And those people might donate). However to keep the ones around who do spend money, you'll still need the ones who'll play for free. (I personally like having a large pool of people to play with)
I'm all for having a cash shop full of convenience and cosmetic items, but skill resets allow you to play your character dynamically and adjust to evolving builds, and potential balance changes.
Personally... I'd make it cost 100,000z for the first time you do it in a week and 500,000z for each time after. It'll reset down to 100,000z each week. This'll let people who make mistakes with their build not be too harshly punished early, and won't be too much of a hassle for those at the end game.
I agree something like this is ideal and should be implemented