They could always, you know, not strip BLMs of half their shielding -- one of them originally a 100% physical mitigation tool on a ridiculously short CD -- and their previously unique anti-magic external...
No one has asked for Physick itself to be buffed. They've been asking that it use one's primary stat, a fundamental given for all other actions and their users, such that it's not as exactly as weak at level 70 as at ~level 20. It is literally stronger in the Cutter's Cry set, just prior to splitting Intelligence from Mind, than on a i370 level 70. That should not be the case.
Might and Mend can still be retroactively adjusted upon equipping the SMN job crystal not to include healing, or to include only one's healing done to one's pets, in order to reduce it from an effective 400 potency to 280, still lacking the dualcast or burst-heal advantages of RDM. Further, one could increase RDM's Vercure back up to 400 potency, increasing its efficiency by some 14.3%, such that its healing potential, too, is about double its damage potential.
In either case there's no reason to leave Physick dead in the water, nor to make it any more powerful via a CD effect (say, competing with Bard) than it ought to be.
If bloat seems an issue, I'd argue that what you should be looking at is Sustain. Attach a HoT component to Physick if/when cast on your pet, and Sustain becomes useless, all without losing that broader functionality.
But, why, though? It makes sense to split the two jobs' experience gains at their branching point if and only if there are lucrative future branched job ideas or if the gameplay Summoner and/or Scholar will, at the only level developers really seem to care about (level cap), improve based on a complete revision of their bottom end actions. So far neither of those things have been hinted at, while the systems already in place could just as easily allow the developers to decide which actions will or will not transfer from Arcanist to Summoner or Scholar; a Scholar's Arcanist (i.e. 1-30) traits are already retroactively changed when equipping the Scholar stone. A split isn't required to trim Physick or Resurrection from Summoner nor, say, Shadowflare or Bane from Scholar, let alone adjust their effects within either job.
So the real question then becomes... why bother? Apart from the leveling imbalance that's already been around through the entire life of Yoshida XIV, is there any real benefit?
I disagree also with the idea that giving Summoner a heal that isn't wholly just a joke would somehow kill Vercure, and by extent RDM. RDM is not Vercure, and Vercure would still retain a number of advantages.
Moreover, you're looking at two jobs that are already foils to each other in terms of general viability. Summoner is the most solid of all casters, and a top 4 performer among DPS. RDM is notoriously... far from either of those qualities. Far greater mana strain from raising, Embolden poor practical parity, necessarily poor CD alignment, and the like are just the tip of the iceberg for that job.
Let's balance those issues before we decide conclusively what offside mechanics should be barred to either, 'button bloat and design waste be damned'.
And let's be clear about this: BLM already had its answer to Resurrection in the form of LB-padding Manawall atop its Manaward atop its Apocatastasis. Sure its cross-classed Swiftcast meant a lot more to SMN/SCH than their Physick meant to BLM, but the unique options had their balancing points. Those were since removed, with nothing being provided in their place.
And then there's the poor parity between, say, Drain and Bloodbath... The caster situation is subtlety to obviously problematic no matter how you look at it. So, yes, such fixes should come first, but to say that SMN should lose utility, or -- as a rule -- be left with obvious crumbled holes in its toolkit, just because it's currently doing well seems ridiculous to me.