-Issue-
Most proc buff/debuffs have different names/icons. For example, when Serendipity on a priest procs it's called "Serendipity" and shows a little speed blazzing mana icon. However, what this is telling you is your Greater Heal is now ready to be cast.

-Solution-
An option to show a different icon when the buff/debuff occurs/is missing, rather than the icon of the actual buff/debuff being monitored. In the example above, it would be great to show the "Greater Heal" icon instead of the "Serendipity" icon.

That's what the custom texture option is for, and is available for all icon types.