Fast forward, because most of the in-between battles would be fine: The Fishermen, Gimblebock, Marli and Barton's Mercs, etc.
Dank Crypt Encounter = 6 skeletons. 2 should be level 1 mages. 4 should be typical skeletons. I think it's totally fine to be able to disarm them first. Makes sense and if you go with that strategy, it would then make the fight easier. Either way, you should not face 4 magic using skeletons. 1 or 2 is good with 4 grunts. That's a solid encounter.
Grove Entrance First Encounter (based on story, the number of enemies should be greater because they make such a big deal about you being a hero who saved the grove from this raiding goblin band, and by this time you should have at least a party of 6) = 2 goblin bosses, 1 bugbear, 1 bugbear chief, 2 worgs, 6 goblins, 2 goblin booyahgs, 2 ogres who toss goblins up to the walls.
This fight seems huge, but it doesn't have to be. The goblins think they are going to overpower the grove and slaughter everyone, especially Aradin and his two party members. So, instead, you show up and ambush them. The AI could be built in such a way so that once you attack, one of the two goblin bosses panics and calls for a retreat. They don't know who's attacking them or how many, and they believe it's an ambush; a trap. "It's a trap!" one cries, and then he calls for a retreat. Then you can choose to either chase them while they are trying to flee, shooting them in the back, or you can let them go.
This would then explain why Zevlor is so upset that Aradin led the goblins to the grove. He knows they've gotten away, and so he's upset because he knows they'll be back. So, now they have to start packing because they'll need to risk leaving before the goblins return... unless YOU do something to save them. NOW you're a great big hero who's going to save them from certain doom because you not only chased off the raiding party but you're agreeing to do something to stop the goblins from returning in greater numbers.
Not every fight has to be a slaughter everything fest. Therefore, not every fight has to be so dramatically long when you have huge numbers. Let the enemies get routed and flee. That's more realistic anyway. Most enemies don't fight you to the death. They fight you until they perceive that they aren't going to win. Then they retreat.
As for the Sazza situation, if the goblin raiders escape, well then it's not as important that Sazza tells Minthara where the grove is. However, they could change her dialogue lines so that instead of saying, "I know where the grove is," she could say, "I know of a secret entrance into the grove, Boss-Lady. There's these tunnels that me and some o' the others snuck into before I got caught. There's statues there, and such, but it's a way in we could use. Some explosives would make short work o' them statues and we'd be able to gain easy access into the grove."
Now, rescuing Sazza and telling Minthara about the secret tunnels would make for a different avenue that the game could go, a battle in the secret tunnels as opposed to on the walls. Now, Minthara's forces that she brings could have more of a chance of success, for the tunnels would be harder for the tielfings and druids to defend than the wall, thus making Sazza's rescue valuable from an evil perspective, and quite detrimental from a good playthrough perspective.
