I doubt he'll see any significant rework, at least not in the way you desire for a few reasons.

First being gobbos are well... crap. They're a cheap, abundant, cannon fodder creature that at best is skirmishy and sneaky. There isn't really a higher tier gobbo unit that exists besides the aracknarok and in lore maybe gigantic spider riders or even less likely lil big 'uns(pretty much a goblins version of an orc nob but pretty sure this got reconned long ago) and the game doesn't consider an arack a gobbo unit.

So all that leaves him really is to synergize better with existing late game gobbo units; skulkers and night gobbos. Skulkers in groms army should be pretty decent given all the buffs while at best still being mediocre in your other armies, since in respect to cauldron buffs; frenzy on an AP unit and 10% phys res or 8 MD for an extremely fragile one won't make them all that much more useful. As for night gobbos, none of groms skill tree passives affect them (besides the 10% phys res of his strarting trait) and they already come with frenzy so the cauldron doesn't do squat for them either. I suspect the reason for this is so he doesn't overtake skarsnik as the night gobbo leader.

So all in all you're right when you say grom is a starter gobbo (common, forest, and archer) lord but thematically that's kinda exactly what he's meant to be and he feels good doing it. Will his mostly gobbo army be able to match 1 for 1 other late game lord comps? Certainly not but his army costs almost nothing, esp if you pick up redux on the bottom line tree and its very powerful considering. Meanwhile you can stack other gobbos armies on his head to pillage and plunder far and wide and with 1 turn gobbo global recruitment (besides skulkers and night gobbos unfrotunately which imo should be changed to 1) you can maintain steam abroad. Does it feel less rewarding having your LL schlep around crap tier units for the entire game? Prob but at least he's not nearly as bad as faye enchantress :( and it's still both effective and thematically sound.

I think the best you can hope that won't take significant redesign of both grom and skarsnik is for CA to make groms skill tree work with night gobbos, because +5 MA +10 Armor and +5 MA +5BvL on armored squig hoppers would be pretty damn legit and at least night gobbos in groms army wouldn't suck. Then maybe just give some small factionwide boost to night gobbos in skarsniks faction, prob in the same vein has the questionable 4% factionwide ward save he gets off prodder. But given that grom and skarsnik feel fine as is I doubt we'll see changes like that, at least not anytime soon considering greenies are going to be too preoccupied with all the incoming nerfs.

Cool, thanks for the thoughtful response. I really do need to get deeper into my campaign before I make too many critical judgments. I posted at a point where I had just rolled over Imrik and the Wood Elves fairly easily on Very Hard/Hard with a bunch of basic Goblins that felt overpowered, and then didn't feel excited about the Night Goblins I had just unlocked. To be fair, it's not on legendary or anything, I did have a double-stack of goblins going, and this is probably when Grom is at about his strongest point.

It sounds like, if I'm reading correctly, Grom does actually synergize pretty well with Skulkers and Forest Goblins, which wasn't clear to me reading his skill tree. I'll have to look into it.

Yeah, all those buffs on armored squig hoppers would be crazy strong, likely too strong but could be fun. I didn't hear about the Greenskin nerfs yet so I'll have to keep my eyes peeled for that info.

Yeah he synergizes with forest gobbos really well; my end game comp for grom (I play with combined caps so this might not be max effectiveness for you) is Grom ,1x hag, 6x river trolls for their debuff aura which you spread out in a line right behind your gobbo line, 8-12 forest gobbos, and the rest aracknaroks for dedicated antilarge on the rears or flanks. That way you only need to invest into 2 trees on his army skill line for a complete army that has very few weaknesses. I use forest gobbos because they scale with literally every buff you'll be getting and they're fast enough to keep up with your trolls and aracks. Skulkers get 40 movement too and scale off all groms buffs (less so with cauldron frenzy) so they should be a perfect replacement for forest gobbos as well.

Lastly the recipe I use is Morks blood pudding with gobbo legs, monster goo, hard shell crab, and hell pepper shrooms. This gives groms army flame attacks, your gobbos factiionswide frenzy and 10% phys res that stacks ontop of the 10% they already get off grom, gives your troll line factionwide flammable attacks which in turn buffs the damage of your entire fire based army, 25% fire resistance for all the fire flinging crap you'll be contending with on ulthuan, and a good AoE spell for if you're doing a head to head and the enemy player boxes or holds one of those stupid bridge maps on ulthuan,... which is way more often than i'd like. Also your orc units will get berserk factionwide (garrisons armies aplenty) and they will lay down the hurt in any engagement and make your other late game blorc armies just monstruous.

As for the nerfs I just gave a quick gander at the changelog during the Kings and Raiders beta and it seems like they're just getting their health reduced factionwide. Not really the change I woulda made personally but I guess orcs had it coming. Orcs are slow as hell so I feel like they need to be beef cakes to contend with skirmishy, ranged, magic, and arty factions. Would rather they just have had reduced killyness, like removing boyz BvI and lowering blorc weapons strength. Or just lowering models in general rather than health per model. At the end of the day it's w/e, there's very few balance changes SFO team has made recently that I've disagreed with so I trust their judgement.

Just a quick follow-up, since it may help someone else who is uncertain/confused. Grom seems to buff all Goblin units BESIDES night goblins. He buffs Forest Goblins, Nasty Skulkers, Goblin Wolf Riders/Rider Archers and, I have to assume, Forest Goblin Spider Riders. I haven't confirmed the Spider Rider units, but I don't see why it would work for the wolves and not the spiders. He does NOT buff Night Goblins, Night Goblin Fanatics, or Night Goblin Squig Hoppers. Thanks for your help Ghilgamesch.