So, here is my feedback: there is not much point in jumping 4 blocks in height! Suppose you can jump to 4 blocks, you have 3 blocks to create something. But to be sure of the success of the jump, you need to leave in reserve another block or two. You have 2 blocks - it’s easier to put two steps and that’s all.
Maybe you’ll think about complicating the achievement of the maximum of this skill, simply adding in the last few abilities of Agility the coefficient increasing the height of the jump?
Simply increasing the character’s ability to be more mobile, you increase the number of unique ideas for construction, which means - more variety. And if you reduce mobility then, it seems to me, people will try to compensate this shortcoming by creating more portals. Please think about it.