This problem is countered by the fact that Bane has a short cooldown and can be used to spread to additional enemies when it runs down-- this is still very effective when you use Contagion. You can spam miasma II if MP allows as well, the continuing dot plus the contact damage from the spell adds up and is worthwhile if you have a large group of enemies. I have no problem doing 15 min WPs on SMN, even with 2 SMN.
The power level of the dots spread is sufficient that SMN would be easily outdamaging other AoE sources if bane spread to all enemies in one shot.
Bulllcrap. You can speed run with 2 summoners just fine. It's not #1 *the fastest*, but it's plenty fast enough.
