If you have any spell failure chance, then something's seriously wrong (unless you're suffering Spell Feedback, which is a flat 35%). Antimagic gear doesn't just disrupt spellcasting; it also severely slashes your spellpower and regularly shuts off sustains.
Currently running a non-AM Brawler, and it'd be nice to see how impaired my teleportation rune is when I'm wearing AM gloves. Just an actual example - good idea. Alternatively, the mouseover text of the arcane disruption icon could stand to be specific.
I have my reasons for having any arcane spell failure. (something in my druid addon)
I can calculate these hidden values myself, but it would save time and be easier for others if it was listed somewhere.
Might have made it easier for those people who didn't know what an arcane disrupting power source meant too.
My feedback meter decays into coding. Give me feedback and I make mods.