Thank you Emma,
I do recognize we have a lot of common points even if our opinion vary on companion usage. I see companions in a more generic aspect to accommodate a more general player taste and to serve a particular roleplaying in Oblivion. Specialized and story driven companions do not attract me in my gameplay style. I can give you examples of "very popular" companions (Ruined Tale, Legacy, ... Suteric_Dreams romance characters) who never made it in my setup.
I give you example of my current character which is Assassin (stealth character); with CSR I created four companions:
One Imperial Class "Healer"
One Imperial Class "Warrior"
One Wood Elf, "Hunter"
One Breton, "Mage".
I tested all these characters in fights during all the preceeding weeks and I found the most suitable to my character in the Mage Breton !!!
Now if I look at Vijla, Neeshka or Rhianna Redux, what are their class? Are they coming with a set of pre defined spells?
What I look for is a "normal NPC", a character that can fit a lot of rolepalying situations without being overpowered or underpowered or hyper-tweaked.
You know, your words put a big smile on my face, because it reminds me so very much of someone...
I see that you registred here in 2007, so maybe the name Grumpy doesn't ring a bell for you...
Grumpy invented the warp-system that all modern companions are based on, both in Morrowind and Oblivion. Grumpy built the first companion templates for others to use, Grumpy made a number of Morrowind companions to cater for various player styles.
He was my closest friend in the ES-community, and I have no idea how many hours we spent on msn discussing "unique" companions with personality versus companions that had so little dialog that the players could roleplay them any way he wanted.
Grumpy would have grinned when he read this and then he would have said: "See there, this clever man agrees with ME!"
Alas, Grumpy passed away in june 2005. Shortly after the release of the only companion where he played part in fleshing out a personality - Thief Companion Constance for Morrowind.
That was on a side-note, but I still wanted to mention it. Because even if I personally enjoy working on 'unique' companions with personality, I both understand and appreciate your point of view. And if I have to choose between a half-done 'fleshed out' companion with a personality or dialog that i don't particularly like or a 'neutral' companion where I can make up the dialog and the personality in my own mind, I definitely prefer the neutral one.
In Morrowind, I always had some of my companions and some of Grumpy's in tow, and in Oblivion, I have found Neeshka (and possibly Rhianna) to be the best equivalents of a Grumpy-companion. So, it's generally me, Vilja (who pvssyrs my ears off) and Neeshka (who is cool and silent but with a little background story that I can choose to use or not use in my roleplay). In my next game I'm going to try out the Dating Mod, not because I particularly want to date a npc but because it's, just like Companion Share and Recruit, an opportunity to interact with the game original npcs.
As for your questions:
Neeshka's class is fighter - you can switch between melee and ranged. She is IMO well balanced, but offers a few services that I find a tad bit overpowered an not in character, so I don't use them. I.e. she can heal you without being a healer, she can recharge your magical equipment, fletch arrows for you (fletching arrows I find matches her character quite OK). but these are optional features so I dont use them.
Rhianna is a mage, but she doesn't really use spells apart from healing (from what I have seen, that is... I haven't used her so much ingame). Instead she has a staff that makes her, well, quite powerfull. But if you put the staff in a container, she won't be... (it's the original Rhianna, haven't used the Redux one)
Vilja is a nord alchemist, which means she is a decent fighter as well. The only spell-casting she uses is for healing - nords are better with an axe than with a spellbook. No extra powers are delivered with her, but later on she will have practiced enough healing to offer some healing for you as well. She has some simple services that are not intended to be over-powered - she'll make simple potions if you give her the right ingredients, she'll go shopping for you but you rarely get things that are worth more than the money you gave her, she'll make you an outfit if you give her a cloth but it's no fancy stuff that you can sell to get rich, it's just there for the immersion. Although she has a story on her own it's not 'forced' on you... parts on it she'll do, herself, as you travel, other parts you have to help her with, but it's up to you to decide where, when and if.
I think that your Breton Mage is probably a better choice than any of these if you play an assassin character. (although the new version of Vilja will have one major advantage... you can fully control her combat behaviour so that she won't rush ahead when you want to sneak). Rhianna I don't know well enough to have a real opinion on, but I think that both Neeshka (if you can disregard her optional services) and Vilja (if you can live with that she has a predefined personality and background) can fit a lot of rolepalying situations without being overpowered or underpowered or hyper-tweaked. Non of them are romance companions, and they won't force you to play the game 'their' way instead of yours. If you get tired of their company, you can leave them behind indefinitely, and just return when you have use for them for a while.
I think you should give them a try
BTW... I recently added two new companions to my group - Valeria and Vincente. I think they might be what you are looking for, as you can tailor their class ingame and they do not come with any story. I have however not tried them out long enough to have a real opinion on how powerful, well-functioning etc they are. And then of course there are the CM Partners, but I'm sure you use them already.
PS ...Grumpy eventually admitted that he, in spite of his opinions, always had at least one of my companions in tow, together with his own.
P PS ...One reason why I think you should actually give Vilja a try: I don't think there exist any companion for Oblivion that resembles of her. I.e. she has very little in common with the "very popular" companions you are refering to. It's like saying that you won't like football because you played guitar once and didn't like it much. If you see what I mean.