It's way too niche, the only time You would really want is in a game mode where you can't heal by recalling and it's going to be high death. (ARAM, Ascension)
Though I wouldn't actually move it lower on the defense tree. The Defense tree isn't that good to begin with, and I really wouldn't swap it with anything else already on the tree.
[{quoted}](name=Valkyrie Witch,realm=NA,application-id=3ErqAdtq,discussion-id=EaiEbe3v,comment-id=0000,timestamp=2015-05-19T18:18:28.867+0000)
Regenerate the shield every time a health potion or Flask finishes its heal-over-time.
Too much, I think it would at least be better if it replenished every time you go to the fountain. It's not like it's a big shield anyway.