It's just a matter of time available to play, vs what you feel like playing. You are not fond of casting, so your one spell caster gets left to rot. Quite frankly, as long as you don't have anything really invested in it, I'd say you can dump it if you want to try something else you might find fun. The only caster builds I can see you with are something like the Soul Survivor (Warforged Favored Soul Melee build), Half-Elven Avenger (Mirys, basically), or maybe a melee Cleric built around Radiant Servant. Maybe Tukaw (Sorc 12, Rogue 2, Paladin 6), but that's one that may be a bit beyond any of our ability to set up right now.
I'm actually considering the Soul Survivor for Rachail's TR, since the extra healing amp from the pally past life helps counter one major WF weakness, and I can get some gear built up to help with that later. It depends on who does what, I intend to fill in a blank slot, basically.
I've tended to run Mirys solo lately, because she basically can fill both Aerii and Rachail's roles at the same time. Whereas Rachail is basically pure melee, and I'm not as fond of that playstyle as others. I cleared the Vale explorers with Mirys far faster and easier than I could have begun to with Rachail. Despite being 3 levels down (and two below level for the area).
One of my main points with Aerii is she cannot do anything in areas where critters have high spell resistance; I burn too many sp and can't heal as effectively. As an elf, I had to put more effort to get a viable CON, so she can't melee effectively even when buffed. She turns into a heal bot, basically, and not a Cleric. Mirys has more hitpoints at 15 than Aerii does at 18. And she isn't wearing a Minos due to using the Wrath set. She'd be close to Rachail otherwise.
Murii gets run occasionally, but since thats more for helping out Corwin's lower levels, I really can't do much.