Hi, I tried my luck on making a recipe for a legendary infusion.
You can check out the rough sketch here: https://i.ibb.co/MZjHd3p/Legendary-Infusion.png
My idea was to make only one Infusion which could then be used infinitely. This Infusion would also count as an Enrichment when slotted into an amulet.
You would need 3 of each +9 stat Infusion, 3 of each WvW stat Infusion and one of each Enrichment plus the Account Swim Speed Infusion.
All in all the price for this legendary would be around 3000g right now (I think). It would include one stack of each T1 and T2 mats, because I think they're heavily underused and the low amount of stat bonus is not really worth higher mats in my opinion. Also higher tier mats would ramp up the price significantly.
The "precursor" is made of the 48 stat infusions from PvE and WvW. People who have played WvW for a long time could actually get the WvW infusions kinda for free, but hardcore Fractal players could also have theirs kinda for free. Even as a newbie you could farm everything in some weeks to months, depending on how hard you want to farm.
The "gift" would be made of one of each Enrichment (because they need mainly laurels which are not easy to get), the account swim infusion and the T1 and T2 mats. Also the classic 77 Clovers and 250 MC. (Just reworked the Gift of Fortune a bit.)
The last 2 items needed for this recipe should be gained by some collection achievement like with Coalescence. Not costly but time consuming or requiring some skill.
The outcome should be one Infusion with infinite uses that would turn into an Enrichment when placed in an amulet or become a Account Swim Speed Infusion if placed in the Aqua Breather.
It could also just give 25 Infusions which would kinda be the same.
Also, after crafting the Legendary Infusion, the standard amount of AR is +9, but crafting higher infusions and binding them to your account would unlock this infusion to all your slots. So if you craft one +20 Infusion and bind it, you can have 360 AR. The +20 Infusion shouldn't be lost then, so that you could upgrade it to +21.
Regarding cosmetic infusions, those should get their own wardrobe like selection for each of your slots if you bind one of them to your account. That way you can decide to wear them just on one slot or wear every cosmetic you have on all the different slots you have.
And my last point would be that the WvW +1% damage bonus should be active besides the AR, so you don't have to switch it.
Thanks for reading.