I usually play Unholy in PvE but i wanted to try out Frost since the 5.2 changes.
While Unholy has no problems keeping both diseases up on ALL targets nearby (due to plague strike causing both diseases and blood boil+roiling blood being their default "aoe spam" spell), i find having serious trouble as Frost keeping Blood Plague up - especially in AoE situations.
When AoEing as frost i always end up having more Unholy runes than i can spend on DeathnDecay - so naturally i spend them on Plague Strike, since my Frost runes are being spent on Howling Blast (no obliterate).
However i EASILY lose track of how long does Blood Plague last on other targets (not my primary one in aoe), which usually ends up so that i only have Blood Plague on my primary target (due to URune spending on Plague Strike) - or i too soon waste a rune on Blood Boil(roiling blood), so that most of the old Blood Plagues duration is wasted.
In short, aside from installing annoying multi-target dot tracking addons, is there an easy way to know (as frost) how long my blood plagues have remaining duration on targets that are not my main target (aside from spamming TAB TAB every time i want to check)?