Not sure if this is the direction I want to go with {+} abilities. Tying them to perforated stubs does help the Riding the Dilu Horse problem, though.

Doesn't this introduce a memory problem if used on a creature with bequeath? There's no way to track this, right?

Yeah, this definitely opens up a memory issues hole for later, especially on creatures with bequeath (same with the School rare land cycle). It's more of a test of concept than anything, to see if playtesters will be okay with cards that create abilities that last indefinitely if there was a significant mechanical reason for it, and there would be markers to help with memory included in packs. This and Unceasing Anger are first on the chopping block if {+} abilities prove to be too unwieldly.