With how scripted this game is though it shouldn't be a problem once you learn the fights I would think. The only one I see being potentially problematic is Deep Freeze so you just have to find an opening once a minute and there's Veil if you get targeted. Plus if you do have to move you can still get part of the effect so it's not a total loss like a cast would be. As for Evil Mist you can move and re-channel no problem or just multi-dot and spam Paroxysm from afar if you really need to.
1. They are mismatched but you never really notice dot ticks happening, if it is a problem the cast time could be changed to 1.5 or 3s but spell speed could always mess it up. Nothing wrong with Shadowbolt, it's just boring. Umm with that change the chance for the dots' additional effects could be increased slightly and the base dmg of either Degenerate or the dots increased so yeah that could work but I don't see the need. Would make balancing easier I guess.My primary suggestions would be
1. Changing the nature of the filler. The GCD is 2.5 and Server ticks are 3.0. I can see this being a little off kilter. Nothing wrong with Shadowbolt.
2. The DoT reduction from the filler can be repurposed into a separate short CD ability (30-45s) that has a similar function, with a more pronounced effect as it's no longer on not-shadowbolt.
3. The Demonform timer seems unnecessarily short and likely a product of having the comparison from WoW. 10 seconds is an extremely small window of capitalization in FF14. 20-30s is more in line with FF14's pacing, and adjust auracite gain and Summon length accordingly.
2. Hrmm less consistency but more burst potential, that'd require more forethought, might not feel good refreshing dots then using that then having to refresh them again shortly after and if their extra effects procced that's a lot of stuff to deal with at once, would all of that be annoying or fun for a short cd? Another thing I'd like to play test. ><
3. It lasts 10s because it can be extended by sacrificing summons while it's active (notice Doomsday has a 15s timer and has to be used within this cd). So if you plan ahead and have a few summons up + enough Auracite for a couple more + Osmose you can extend it quite a bit, and everything is sped up during that cd so it's easier to handle everything going on.