We learn very early on that Rhode has been released from prison and is now on the exact same quest you are. Interesting. A chapter that had apparently been closed has been reopened. We follow Rhode's footsteps through Aleroth, one final confrontation seems inevitable and then...
It doesn't happen. Bellegar's turned her to stone.
Gosh.
That's... that's really not a fitting end for Rhode's arc. Throughout your previous encounters, you could try to reconcile with her or make her even more angry. Whatever approach towards Rhode you decided on it would have been... fitting... if you could actually resolve this issue between the two of you.
In Flames of Vengeance you and Rhode are demonstrably on the same side, working towards the exact same goal. Is Rhode still too consumed by her own hatred to listen to reason? Is she willing to put aside her distrust so long as this common enemy looms in the air? Might she actually be able to reconcile with you?
None of these resolutions are particularly original, I'll admit, but they work. Flames of Vengeance dangles a new story thread about Rhode in front of you, but instead of doing anything with it, it rips it away and carelessly discards.
There is no confrontation, there is no resolution. Bellegar's simply turned her to stone. Just like that. And you weren't even there.
It's like if you finally manage to escort that zeppelin to the final boss fight, you finally face Ygerna and then!
Bellegar warps in, kills Ygerna and warps back out. Game Over. Roll Credits.
You'd feel cheated if that were to happen, wouldn't you? The Rhode thing is not nearly as severe, of course, but it's still there.