I made a fun test with a friend Summoner of my FC. We are both level 50, Mi'Qote of the sun. I'm mainly scholar, so full MND, she's mainly summoner, so full INT.
Our stuff is more or less the same. Level 45/50 blue armor from class quest, basic accessories level 46/49, and the book is the one we need for the relic quest, before Ifrit's weapon.

We tested our DOTs on dummies. Her in summoner, me in scholar with cleric stance. (In this configuration, she has around 15 more INT than me).

My dots do WAY more damages than hers. When the full set of DOTS (Miasma, Bio II, Bio and Thunder) does around 245/250 per tick for her, the same set does around 280/285 for me.