Normally I wouldn't make a post about one random festival item, but I think this item existing in its current form will limit the item team enough for it to be warranted.
As it stands, Verglas spirit is the ONLY item in the game that uses heavy - max mana as a debuff whilst also effectively removing your ability to invest into intelligence. This means that to make the item somewhat usable, there were VERY heavy buffs given to it. Verglas Spirit gives more than double the Mana Regen of the the next best non int armor (excluding scale of seiryu, of course), and a lot of raw spell damage to boot. Right now, many players consider this item outclassed because Skidbladnir gives everything Verglas gives besides the Really Really high mana regen and you don't lose access to half your mana bar to use them. However; if the item team starts to fiddle around with giving +Max Mana to other non-int items like they already have with Brocach, they can turn this seemingly outclassed pair of boots into a no int sustain machine. The only reason I think this should be reworked now is because this limits the design space the item team members have. Now, if an item team member wants to make an item with the max mana id and no intelligence requirement, they have to be aware that there are a pair of boots that give 35 mana regen and near the stats of Skidbladnir that will then become possibly usable and really good with Brainwash waiting around the corner if they so think to give an item a good max mana stat.
I believe that these boots existing will limit what the item team can do with the max mana id (i know the community wants to see that id on more items) and I think seeing them reworked now before they become some powerhouse that gets nerfed in the future and or limits item design is warranted. ok ty :D I hope you all have a good day/night!
tl;dr : i think verglas spirit will stop the item team from using the max mana id to its fullest fun usecases