I was thinking that it would be much easier to keep track of short duration buffs, debuffs, and DoT effects if upon expiring there was a visual effect. The icons are quite small and sometimes I won't notice that an ally's Protect is gone immediately.

At the moment my solution is to AoE cast buffs on both myself and my party so that when mine are gone it means that they've all expired. This just doesn't work well because Protect, for example, has a fairly small AoE range. So it ends up being that you have to huddle together to do this properly!

I was thinking the animation could look something like a shattering version of the actual spell's animation. It would have a dissipating effect before fading, something to really say to the caster "This just disappeared, recast it!".