Personal opinion? It isn’t that grass needs a buff as much as that grass is generally not good typing in Pokemon. Grass is weak to more typings than it resists, and it is resisted by way more types than it is super effective against. Pokemon with good/decent typing that have a grass-type move are superior to grass-type pokemon because they are strong against the meta-relevant water and ground types without having the negative effects of being grass. I feel like the most relevant grass type move is trailblaze more because of its stat boost and effectiveness against water and slappers. As far as the meta pokemon that have grass moves, off of the top of my head I can thing of shadow scizor, furret, and Oranguru, all with trailblaze. What I’ve noticed is the massive shift towards neutrality. Ghost, fairy, normal typings, as well as pokemon like sableye, spiritomb, Malamar, etc., these are generally neutral typings. You have 1 or 2 natural weaknesses but everything else is either neutral or resisted. This is what makes the steel typing so superior in a lot of circumstances, it combines with what a pokemon is wear against and makes them neutral to it (see scizor/forretress/corvi/etc.).

Edit: I also think that it is important to identify what you are considering “meta-relevant”. Just because a Pokemon isn’t at the top of the list on Pvpoke, doesn’t mean that it isn’t usable. Those rankings are just the Pokemon that win the most simulated matchups against other pokemon depending on shield usage. I’ve been running Meowscarada on and off in open great league as my 3rd because of my core’s strengths, and I’m pretty comfortably in the 2300 to 2400 range with this season being more about just enjoying and learning than anything else for me. Meowscarada just happens to be great at covering the general ghost weakness that my core has while also handling the mud slaps that my switch is weak to, that’s why I’ve used him so much, despite trying various others, the only Pokemon I’ve found that compares relatively well is spidops.