Thanks for the tip
I know that when it comes to aesthetics it's nearly impossible to be objective, but in this instance I don't think it's out of bounds to say that the effect on the right is empirically worse than the effect to the left. Even if I try, it's very hard to defend it as an intentional change.
I don't think it is intentional, though. I've googled a little around on this issue and the general consensus seems to be that in Warlords of Draenor they updated the Holy Light healing spell effect, and the /Use effect on the tabard was just a larger version of that effect and so the tabard got caught in the crossfire. I don't know any of this for sure though, since I haven't seen any official Blizzard posts that state anything at all about altered effect.
Do you personally think it's fine the way it is right now?