Can someone give me an in-depth explanation why Summoner is arguably the worst DPS?

[Viviza]

I guess that's something... but come on, really, SE?! That's it?! What about a higher base piety and a shorter enkindle and anything else that would help a bit? =_=

Step 1. Collectively argue that MP consumption is a major problem for summoners
Step 2. SE announces reduced cost on certain summoner spells
Step 3. Complain a lot about the announcement
Step 4. ???