As others have said, there's a great deal of fascinating possibility in further efforts of diplomacy, foreshadowing of the other kingdoms, and working with the Stag Lord, Hagrulka, and others running off their own version of kingdom rules to expand their territory in response to the PCs. All the opposing kingdoms seem to end up too small - Varnhold is barely a village compared to what the PCs will have when they interact with it (for seemingly no reason, since Maegar Varn doesn't seem to be particularly weak or a fool); Fort Drelev is a single city; and Pitax is also a single city.
But these may be beyond the scope of the rewrite, since many of them involve heavily reworking the campaign itself.
On the just encounters score:
- The Dancing Lady is in the hard/frustrating category. She doesn't pose much of a threat, slowly clawing PCs to death, but she has multiple options that just remove PCs from combat immediately, leading to long, slow fights of whoever isn't dancing slowly beating her down while the rest of the players twiddle their thumbs for 12 rounds.
- Cephal Lorentus, Vordekai's undead wizard is a pretty consistent weak link. The terrain is interesting, but Cephal himself has almost no capacity to threaten the PCs, no defences, no minions, and no great tactics. He's easily mulched to the point of wondering why there's even a fight here.
- Vordekai is about perfect, a deadly threat if treated lightly, quite crushable by those who have done their research and come prepared.
- Hannis Drelev, to me, seems to be an overpowered encounter. Not compared to what CR the PCs can handle, but in terms of what Drelev appears to be. He's a whimpering coward who loses every fight he's in, backstabs the PCs, is hated by his own kingdom, and is barely maintaining control. But somehow in all this he's 12th level. Even the text itself mocks him, with Drelev "fancying himself a skilled swordsman". Even his wife, a diva who has never personally gotten her hands dirty, somehow stands as a CR6 encounter. I think Drelev should be around the same as her - a speedbump for the PCs to mow through, leaving Armag as the 'true' boss on Book 4.