The problem I see is that this insane 2min burst focus would mean one of 2 things:
- 1) Toxikon remains dps neutral - you can happily sit on 3 charges while not needing to move, no loss here. Edge cases of getting another GCD in right before a boss dies/ goes untargetable exists but are rare and happen maybe 2-3 times per fight if at all
- 2) Toxikon is slightly stronger than Dosis - dump all during burst for maximum dps. Obviously you have some small skill ceiling here as you still need to keep enough to cover unavoidable movement that isn't covered by slidecasting, Icarus or dumping a Phlegma charge to avoid overcapping but it's not that much either. You'll eventually arrive at a point where you use the majority during burst.
Perhaps if it remains dps neutral but they build more on MP free aspect by lowering SGE's overall MP gain from Addersgall it could be enough of an incentive to regularly use it both for movement and MP as part of your normal rotation. 
I could also see them give us an Eukrasian Toxikon. I think SGE in general could be more focused on multi-purpose tools that you modify as necessary with Eukrasia (and if only they hadn't made Dyskrasia into an aoe that skill as well ...). Eukrasian Phlegma, Eukrasian Pneuma, Eukrasian Toxikon... there are enough options and even if some of them will lose value over time as you get better/ better gear, it's preferable over having niche skills that take up a slot and get used in terrible groups and/ or prog maybe once in a blue moon.
Things like Eukrasian Toxikon dealing slightly lower damage than Dosis/ regular Toxikon but restoring MP. It becomes a great recovery tool after death or when things went sideways and you had to GCD heal/ ress a lot. Or Toxikon could be a bit stronger than Dosis and Eukrasian Toxikon would be equal to Dosis. 
Eukrasian Pneuma could heal less in total but also apply a shield, especially valuable in prog but there are also cases when the full 900 potency heal would be too much and with that modification you'd still get 100% value, just at the price of slightly lower potency overall. Would also make Pneuma more flexible.
(And for god's sake, stop letting SGE shields block SCH shields while also taking priority over them already...)