Master Summoner please help me.

[Judge_Xero]

Even though we might not be the most loved class in dungeons.....

I'm still not sure why this is.

Even on pulls larger than 4 mobs I find Summoner AOE is pretty good. Starting with Shadow Flare and Miasma II while the Tank is grouping up the Mobs.
When the mobs are grouped you can DoT up an outside one and Bane. Then DoT up another that is centered between Mobs that Bane missed to further spread Bane. (up to 8 mobs)
Only about 6 GCD before you have your full arsenal out and can start BlizzII spam or keep Miasma II up.

If there's only 7 mobs you can usually Contagion your DoTs and then Bane. Then Blizz spam until Bane is up again and Bane off the mob closest to the ones without DoTs. They'll almost always take priority to get hit.

[Delvish]

I'm still not sure why this is.

Even on pulls larger than 4 mobs I find Summoner AOE is pretty good. Starting with Shadow Flare and Miasma II while the Tank is grouping up the Mobs.
When the mobs are grouped you can DoT up an outside one and Bane. Then DoT up another that is centered between Mobs that Bane missed to further spread Bane. (up to 8 mobs)
Only about 6 GCD before you have your full arsenal out and can start BlizzII spam or keep Miasma II up.

If there's only 7 mobs you can usually Contagion your DoTs and then Bane. Then Blizz spam until Bane is up again and Bane off the mob closest to the ones without DoTs. They'll almost always take priority to get hit.

With 7-8+ mobs, I typically will B2MB+bane one mob on say the right edge of the group, then find another mob on the left edge of the group to B2MB+Bane. This gives maximum uptime on mobs, instead of giving remaining mobs half spent DoTs.