I haven't really checked if this has been discussed before, so sorry if there's already been a thread on it. Using Astrologian earlier today got me thinking, must all healers be casters? Aside from, well, dev things, could a ranger-styled healer that has no cast bars or even mp be possible?
Of the jobs we have right now, I think Astrologian and Sage could be ranger healers while White Mage and Scholar be the caster healers, where the former would heavily rely on doubleweaving oGCDs while constantly being able to move, and the latter has powerful casts with limited mobility to mirror that of their DPS counterparts.
Admittedly, the caster/ranger line's been a little blurred by the SMN rework, and Healers overall have been given a lot more mobility now that many of their cast times have been shortened to that of AST's. However, the main reason AST even had that shorter cast time in the first place was because of the sheer amount of oGCDs it needs to weave from its card system, but its EW rework's increased that load with the way Redraw/Minor Arcana/Astrodyne/Divination now functions, and the single weave window isn't enough for it anymore.
I do think shortening all the other healers' cast times was a correct move considering all healers also got more oGCDs going up to lv90, but the others don't really need to be able to doubleweave nearly as often as AST does. Lightspeed seems to be designed to cover for that, but the timing to use it is heavily dependent on the party and the duty, and it alone is its own oGCD to weave. The job also has little to worry about with MP economy, so at this point I feel it has very little reason to really be a caster at all.
As for SGE, currently Eukrasia's a weird instant cast with its 1s cooldown adding up to a full 2.5s GCD with Dosis/Diagnosis/Prognosis. It also has a gap closer and Toxicon/Phlegma are GCD instant casts it can stockpile, so it's already got a kit that encourages having a lot of mobility. Being able to doubleweave would also make it easier to throw Kardia around, since most of the time, at least for casual content, we just slap it on the MT and leave it there for the entire duty. Its MP economy's not as good as AST, but as long as your Addersgall usage is good I'd argue it's still mostly unnecessary compared to SCH and of course WHM's.
But more importantly, aesthetics. It'd look way cooler to constantly be able to run and gun with floating laser pods. I found both the cast and shot animations of Dosis to look underwhelming compared to Glare/Broil/Malefic. We don't even get to keep the rapid fire Toxicon, which even the EW trailer showcases with Alphinaud, after it upgrades to the cross slash (not that I don't want the latter), and I'd imagine a Dosis without a cast would have a similar enough feel to somewhat make up for that.