It matters because there's no way to choose between text warnings and timer bars for a given ability, so if the Spell Shield warning was changed from a message to a timer bar, my only choices would be to disable Spell Shield warnings altogether or look at a big bar that's irrelevant 99% of the time for me and anyone else who doesn't have cripplingly high latency.
I can see I am not going to make any headway with my plight. Regardless, this is a, "Bossmod" and it's got a meter for just about everything under the sun. I personally feel it's a bit odd this one was left out. Not to mention I've done Maulgar a jillion times *with* the bar and it never got in my way or made me think once, "Dead lord!!! What's with this extra bar???". I mean, isn't that the point of BigWigs' existence anyway? The way it is now there might as well be no warning because I can just as easily see his shield come up versus an instant raid warning.