The CORE of the druid CLASS tree should not be specific skills/abilities that end up being limited or restrictively used only by the related spec. In this case balance and resto druids are rarely going to jump into bear and cat form to use their shapeshift specific skills, and feral and guardian druids, especially guardian, are not going to pop out of form to cast spells to heal or start sun-firing from afar.
There ARE cases where some skills/spells were done right and they are functional and usable to all forms. So things like Soothe, Mighty Bash, Renewal, are good examples of being situational, usable in any form, and don’t force a form change/shift or get in the way of what your main role is.
Some BAD examples of skills/abilities that detract from what your MAIN role is (by way for forcing form change to be used or stopping whatever your role is to do said thing) are things like:
Rip, iron fur, maim, rejuvenation, swift-mend, wild-growth, stampeding roar, etc etc.
You can see these skills all require you to be in the specific form to be used and that’s a problem for a CORE class tree that is supposed to be benefiting ALL specs.
The right side of the tree is pushed into boomkin/resto stuff that the guardian or feral cat form players are not going to jump out of form to start casting. and the left side of the tree has the cat/bear form stuff that your just not going to see a boomkin or resto druid drop what they are doing to go rip, maim, and build rage to iron fur mid combat.
What SHOULD have been done and what SHOULD be changed going forward is making the CORE druid class tree focused on universal skills or passives that impact EVERY spec or are usable REGARDLESS of form.
Yesera’s Gift was a perfect example of something usable by all. Flat damage reduction of bear skin or speed boost be feline quickness are great universals.
Many of the shadowlands skills were also universal like adaptive swarm, convoke the spirits. HOWEVER, those skills are in the SPEC of the tree and not the CORE of the tree which, conceding my bias, is dumb because those are PRIME examples of universal skills that should be in the CORE tree that one can opt to take.
My point being it’s dumb to play a druid spec when half the tree as designed “feels” wasted because whatever your main role is you get little or no benefit from taking said talents nodes in the tree.
TLDR: the core of the Druid class tree should be universal skills or passives that can benefit any spec and any form and not be restricted by said form.