"More than that, you can no longer get Mythical items in any box in the game. The only way to get Mythical items is to transform Legendary items that can turn to a Mythicals. This will require players to really prove they are strong and work in order to reach Mythical items."
So technically the veteran players are still able to use the mythical items obtained earlier, but the new players will have to boost the other tier items in order to get any myths at all? It looks like a middle finger to the new players.
"Inventory limit is a common mechanic in such games to motivate focus of fewer, stronger items rather than hoarding thousands of meaningless ones."
What about the low level items such as Teleport Mark I? What about the other mythical items? We're all gathering all of the mythical tier items (even Combiner Storages because they CAN be useful), we don't know if one of those items may suddenly get a boost and may become the new meta.