RDM should absolutely have Vercure because RDM is RDM. However, in a party, RDM should only ever need to cast Vercure as a Dualcast trigger, never as a heal. Neither job should ever have to heal anyone in group content, and if they do, it means something has gone horribly, horribly wrong, and the situation is outside the realm of intended play and balance considerations. So my argument will consider this from a solo perspective.
SMN's low powered Physick is not a problem, because they got Sustain back. But Sustain isn't that great because the pets themselves are so muted and useless. If you "need" more than Sustain to keep a tank pet alive, the tank pet isn't tanky enough. If you need Physick to keep yourself alive, the tank pet isn't tanky enough.
In a perfect world, a DD pet would be squishier but deal enough damage to kill a level-appropriate enemy before either the pet or master died; and a tank pet would be able to survive against level-appropriate enemies and generate enough enmity to keep level-appropriate enemies off the master.
That the tank pet isn't so great at either of those things is a side effect of how non-petcentric SMN is. 99% of SMN button presses make the SMN do something. I won't argue that they should have to push any fewer buttons than other jobs, but more of those button presses need to make the pet do something instead. The SMN himself should be generating much less enmity and damage, while the pet is a whirlwind of force. If 75-85% of the SMNs actions commanded the pet to do something; and if the SMN himself mostly stood back and supported the pet; and if the pets' stats were rebalanced for the appropriate level of survivability; then we'd be addressing the real problems with SMN as SMN.
Unfortunately, this late in the development/life cycle of the game, SE committing the resources to a fix of this magnitude seems unlikely.
tl;dr: SMN doesn't need a better Physick; they just need to be real SMNs.