If gold has no significant uses outside of respecs, then it wont really matter if you need to pay X% of it.
Gold would then also need to be account based, rather than character based (otherwise you can just move it around before a respec), which would then mean respeccing on one character would make it harder to respec on another. That is not good?
I’d just have a separate currency, “Respec tokens” or whatever, where you can get like 2 each week, up to a cap of 10, with first respec each week costing 1 token, next 2, next 3, next 4. So you can respec up to 4 times in a single week. Though then you cant respec as much for the next few weeks, while you restock.
If you ‘only’ respec once a week on the other hand, you would never run out of tokens. This would be ‘per character’.
I wouldnt be against this currency having other uses as well, making it more gold-like. Then the limit and refresh rate could also be higher.
Like maybe a vendor sold temporary buffs (dmg, defense, Magic Find etc.) for these tokens. And instead the max might be 20 and you got 5 each week. Might also adds a potentially interesting choice of when to use your tokens for a buff, before going for a challenging dungeon or whatever. As well as a choice between respec and a buff of course.
Speaking of respec systems, keep forgetting it, but some people have proposed a “Elders Scroll” style system, where your skills gain power as you use them.
So maybe fireball can get up to 20% more dmg, if you have used it for 10 hours. If you respec, all the skills reset back to default dmg again. I have some issues with that system, but it is a neat way to get completely rid of respec currencies, while still rewarding staying with a build. For those who care about such a thing in games, it could even be considered “immersive”.
One positive aspect is, if you respec, then go out and try the new build and regret it, you can respec again immediately, without losing anything at all (since you already made all your skills go back to default 0% bonus). That solves a lot of the “but what about testing stuff!?” argument.
And of course, a version of that, which I have mentioned before is to mix respec and death penalty together in one system. Could also be mixed with the above.
Like, the longer you stay alive (and kill mobs, so it should be xp gain based), you acquire a magic find bonus (and maybe empower your skills as the above idea).
If you die, part, or all, of this bonus is lost. If you respec, all of the bonus is lost. So if you die a few times, and decide it is time for a respec, the respec might essentially be free, since the bonus was already lost. One good thing about that system imo, is that it is friendly toward those who might need the respec the most; as in those struggling with their current build. While the cost is steeper for those doing just fine with their current build. And like the skill empower idea, multiple respecs quickly after eachother, are completely free.