I doubt that they will be removing DOT's for the sake of removing DoT's. Summoner changes were to make it more about summoning (yeah the rework wasn't really great imo, but thats more because it lacks any real cast times). PLD's DOT's were also a lot more stricter and didn't make sense to keep (even though I prefered how PLD used to play).

I actually think the next caster will focus on DOT's a lot and most jobs with DOT's will stay the same... I can think of some that aren't really important such as circle of scorn that I wouldn't mind being removed.

With the Simplified Jobs, most DOT's don't really even add much complexity outside of something to keep track of if its a upkeep job, Not to say i want DOT's removed or theirs some fun gamplay with DOT's but the jobs being simplified is a big issue... but I don't think that they'd need to remove DOT's for that just look at healer design that has DOT's but they have the most easy and simple DPS kits in the game