The only flaw I see in your proposal Zeroth is that there shouldn't be new rewards using the old Pristine Fractal relics. You'd need a new currency. Beyond the inherent unfairness, the point of such an overhaul would be to encourage players to visit high level fractals, and if they already have the currency sitting unwanted in their banks then it's just free rewards.
And I use the term "unfair" carefully. I don't think anyone should be unnecessarily rewarded for hoarding silk when it was worthless, or hoarding thick leather or ascended rings presently.
That's true, but the people who have that much currency are the more enthusiastic folk, and I don't think rewarding them in this case is inherently bad, specially when they go to stake 0 as soon they spent their current currency on the next day. That's definitely a problem, but I think that fact alone is not enough to pull much weight on the idea of using yet another currency. Besides, it's an account locked feature, so it wouldn't affect other players unfairly.