So I'm just going to put this out there for those of you who like the "reroll all slots every time" principle.

There are 132 possible buffs for the awakened weapon.
There are 4 slots on an arcane weapon that can have a buff in it.

Let's say you're a Luck enthusiast and you really want +5% luck on each of your slots for your primary weapon so you can reroll a whole bunch.
To do this you need to get that 1 buff out of the 132 possible buffs.
This is 1/132 chance per slot to get the buff you want.
Now, since we need to get the same buff in 4 slots, and getting 1 buff has no effect on the outcome of the other slots' buffs, we know that in order to calculate the odds of the 4 buffs we want we need to multiply these odds together.
This is not a simple 4 * 1/132. No, we need to take the odds for each slot and multiply them against each other.
So, in order to get the combination we want, we will need to have luck on our side. The odds of getting our preferred combination is as follows:
(1/132) x (1/132) x (1/132) x (1/132) = 1 in 303,595,776
So in order to get the 1 combination you really want, you will need to either get really lucky or reroll your weapon somewhere around 303,595,776 times.

Now, we know that the number is 303,595,776 rolls to theoretically get your preferred. At a cost of 5 platinum each, this will cost an individual 1,517,978,880 platinum.
If you order the cheapest platinum available (1700, chest full of platinum) this will require 892,929 orders of the chest full of platinum.
At a cost of $89.99 USD per chest of platinum, you will end up spending $80,354,680.71 on this endeavour.
Now I don't know about you, but I certainly don't have $80 million dollars just laying around.


Now consider doing per-slot rerolling.
The same odds from before apply. 132 buffs, we need to fill 4 slots.
The difference in this case is each slot does not affect the previous, so you can reroll 1 slot until you get what you want then move on to the next.
Doing this multiplies the odds by 4 rather than by 132 per slot since, as explained, the other slots do not get rerolled when you reroll a new one.
So now our odds of getting our perfect combo are 1/528. So in theory it would take you 528 rerolls to get your perfect combo.
528 x 5 plat each is 2640 platinum
To get 2640 platinum would require 2 purchases of the chest of platinum.
At $89.99 USD each chest of platinum, it would cost a user $179.98 to get their perfect reroll.
With this method, the users also get more control over what they want their perks to be instead of complete random every time.

Those of you who were really supporting the idea of reroll everything every time, which do you really, realistically, prefer?
For me, it's per-slot reroll. No doubt about it.