1) A GM taking occasional control of other people's characters is not a bad thing, as far as my opinion goes, provided they can do it respectfully and in good taste. I have kinda strange limits that way in that I don't mind if someone moves my character, most especially in situations where they couldn't get out of it anyway, without asking me. But I don't like it when they put words into my character's mouth, or give them thoughts. And, of course, everything is easily circumvented by simply asking, or offering a forewarning at the beginning of gameplay. 

If I was in a group roleplay where I didn't like how the GM was running the show, whether railroading, porwerplaying, metagaming, or bunnying, I'd likely leave. If I really liked the idea, or thought it might be useful, I might explain the particulars before I left, but otherwise, I'd probably just say something like 'sorry, too busy, bowing out.' Ordinarily, however, I'm a shy little pansy who doesn't want to risk starting a war of opinions just to possibly change someone's view on their actions. If I really, really, really liked the idea to start with, I might try to stay on for a little while just to see if things get better, or I might attempt to be as diplomatic and wishy-washy as possible about saying that they could maybe, probably, possibly, just a little, use a bit of redirection in how they're going about their writing. *sinking farther into my chair all the while*


2) I think 1x1 is quite possibly the best ever method of writing that exists. Except possibly really good novels, but that's not collaborative, so, meh. I will expand to 1x1x1, but I prefer small group dynamics over large, mainly because I am a slow poster who does not want to feel like I'm holding anyone up or disappointing more than one person if I can't continue an rp. I also like it because there's only two minds to accommodate when writing, and you can browse the inordinate number of interest checks to try and find exactly what you're looking for. And there really is something for everyone, honest, it's just not always on the same site you're on. :/

One on one's [i]can[/i] most definitively, become a smut fest, or a long running romance, or an oops I have to post to this again, damn it I should just say sorry, no more. If you're looking for well-written multiple paragraphs, detail oriented, character developing posts, you do have to go on a bit of a treasure hunt through the more usual 'M looking for F!' etc. But I assure you, it is a treasure hunt. When you find that partner who is just right for you, whose writing and humour and wondrous ideas resonate with your own, it's a brilliant moment. It might take a while. Indeed, it's taken me ten years to amass all of 10 writers I will never let go. But it's worth every ignored message and not quite as advertised discovery. 

I've never written my own interest check, so it is possible that would help you along in finding these people that are just right for you, indeed, I should hope it does, but I certainly encourage anyone and everyone who's interested to give it a try.

It is very possible to find and maintain a 1x1 storyline that doesn't involve romance or sex. You have to be a little pickier and strict with your fine tooth comb over of each interest check, and the partners you accept, but rpers are certainly capable of it. ;) I have five? I think it's five, on the go right now that do not involve and do not have a future of, romance. I've spoken with quite a few others who weren't looking for it either. I'm not sure about the [i]Her[/i] finding. There's bound to be at least one person out there with a similar desire and drive to write the way you'd appreciate, but the movie, to my mind, was geared towards a romantic relationship, there might not have been any actual sex, but that was not platonic love.... >.> 

Anyway! Yes, go for it! Be prepared for some iffy troubles and discouragement, but do not give up! It is worth the effort to find a writing partner who fits the bill. (and really, really depressing when they vanish off the face of the earth and you can't find them again, but still worth knowing they once existed and might again)