Upon 'analyzing' a couple, the first thing I look at is contact and compatibility. I don't care about so-called 'evidence', gender, or anything. I. want. compatibility.
What makes a successful couple? First, personality--do you think Heero would do well with another stoic character? I don't think so. Lifestyles--one thing I don't like about 1xR is the completely style of living of Heero and Relena. She is a busy business woman wanting above everything good for the people and PEACE. He is a killer who's never had anything to do with what she wanted. There's the help one can give the other, and for GW, after the series, which is covered in other sections. Of course, being an author as well as a reader, I always take a look at fic possibilities and quality of fics already in the fandom.
Just what DO I consider 'valid' pairings? Well, there's Yusuke and Keiko, who make their devotion to each other clear as day (hey, when a guy proposes and asks the girl to wait three years for him, ya know it's something). There's Kurama and Hiei, whose scenes just make you all gooey and tingly (I mean, how often is that HIEI screams someone's name in sheer panic and looks pissed as hell when the most powerful king in Makai asks that someone to his kingdom). There's Zechs and Noin, Trieze and Une, Duo and Hilde, and of course, Heero and Duo.
Notes:
1. Like the Evidence section, I don't really think this proves much or provides unarguable points for 1x2. As I stated in Atsui, if you love something, support it, plus you shouldn't have to defend what you love.
Point made, personality...
I'm certain you've heard this before, but I'll say it again: Heero's and Duo's personalities are just too compatible. Duo's sunny nature offsets Heero's gloomy one, and Heero finally has someone who can bring out the better side of him and has time for him.
This is a relationship which I believe is either love or hate, not both. Either everything works out or nothing does. But since the series pretty much scratches hate out, it leaves me with love. Of any other character in the series, Duo seems to me like the most likely one whom Heero would fall for. Another reason why I believe these two would really be able to hit it off is...well, Duo is very lovable. I can say that a safe 99.5% of the fandom loves Duo. So why shouldn't Heero? The odds are good, the ends are good, and let's not forget that Heero IS human, and it's human nature to love someone like Du-chan. OK, let me clarify. If you take someone who's not very popular, like say, Kans so goes the dub, there's not much of a chance anyone would fall in love with him.
Next, let's take a look at lifestyles.
Forget the Princess and her Kight in Shining Armor! Forget the prince and poor goosegirl! Just remember the two soldiers trapped in a war-racked world with nothing but themselves to rely on. I can't think of a more romantic setting, can you?
Heero's past is filled with war, unhappiness, and sadness. He is a soldier, either killing people or people are trying to kill him. Lovely, isn't it? Being one of the Five, he always stood out in the battlefield. Call me weird, but somehow I don't think he liked it. ^^; Thus my theory that he would probably want to settle down to a completely normal life for a while and just learn to act like a human again. And maybe, just maybe, he will go work for the Preventors or something just so he doesn't loose touch to war COMPLETELY. I mean, after being a soldier all these years, he may feel a little...lost without fighting.
Duo's past is no better than Heero's; pretty much everyone he ever held dear in his childhood died and he was left with this mushroom-head freak whom I really don't think he cared much for. Unlike Heero, he actually seems the type to enjoy a posh enviroment with plenty of attention. Sometimes. He obviously enjoyed gloating after his basketball scene, yet he had no desire to stay with Quatre. I think what he would like is a normal life with the occasional party at Quatre's or Relena's.
But no, this isn't completely OT. We now get on to how Duo can provide Heero with the above mentioned things. Duo is not the heir of a god-darn HUGE family industry, nor is he the only hope for everlasting peace between Earth and the colonies. He's not the best friend of said heir, nor is he so fixated with justice that it fills his world. He is Duo Maxwell, former street rat with survival skills like nothing else! I don't really think he would be under ten cameras at once 24/7 unless he wants to; and I don't think he'd want to. Duo, unlike Relena, Quatre, Zechs, and many other characters, is still in touch with the *wiggles fingers* 'normal' side of life. Call me weird, but I really REALLY don't see Zechs in a house with a white picket fence mowing the lawn. Heero wants a normal life (theory), then he'll try to be normal, and Duo can definately help him.
Duo is a character that I can see with just about every main character in GW with the exception of a few. His personality, I think, is very adaptable, but one thing I noticed is that his mood is really quite unstable. I mean, the Dark Duo is VERY VERY different the Cheery Duo. There is one area I think Heero may be of help to him. A.K.A. Something steady for him to rely on and perhaps cling to if needed.
Then there's the help one can give another.
We've seen how well they work together as a team. Both have superior piloting skills (the others are good too, but it's those two whose skills are really highlighted in the show). Did anyone notice how Heero's more of a programmer/hacker and Duo more of a technician/parts-guy? Bingo! Can we say 50/50? Peanut butter and jelly?
They also seem to have a tendency to pull each other's asses out of trouble. Being prodded and questioned by enemy forces would not be Heero's idea of a successful mission; so Duo blasts him out and hauls out his Gundam. Heero saves Duo from that MS approaching DS from behind; then literally pulls him out of prison despite his state of injury and his uselessness.
Duo has something Heero needs: Connections and discretion. His connection to Howard is one heck of a relief for Heero, and none of his technicians are likely to squeal that there's a Gundam pilot visiting regularly.
Fic possibilities...
Can we say...WHOAH!!!!! ^_^ Those two have more 'alone' scenes than any other couples (except Trowa and Quatre, or Duo and Hilde, but I really really don't think anything went on between them, seeing how the Japanese view unmarried couples living together), which gives them a good chance to develope a relationship. Their first meeting, the second meeting, the time they spent together before New Edwards, the time in that boarding school, and after Heero saves Duo (which I KNOW was quite a long time because just before, Duo could barely sit upright, and now he's seen gripping the bed and being quite mobile with no visible marks at all).
Not only that, there's just so much...fire between them...so much friction, which would make any couple interesting, but not too much that it screeches. Plus take a look at the end of EW. Heero was seen leaving Relena (something which I think is of significance). But WHO did he go to? Duo would be the only logical answer in my book, seeing that he's hands down the closest person to Heero (yup, they're officially 'best friends', and of course there's no reason why friends can't be more...).
Fics overall
1x2x1 fics simply AMAZED me. Would you believe that I'm a former 1xR-nutcase? Well I was until just a couple of years ago, when bad writing in the fandom turned me away (there was nothing to 'fuel the fire' back then). After getting over my homophobic streak, I tried out some 1x2 fics. Amongst the first I read was Madam Hydra's "Maxwell's Demon", a fic deserving its own category. At first I was disappointed at the amount of yaoi in it, but the story was just too good and damn original to be marked down just because of that. Next was Talya's 'First Kiss' trilogy and its sequels "To Go That Far" (a definate classic in the GW fandom, which gave birth to a popular genre known as 'Relena Finds Out') and "If You Love Me" (I've lost track of how many times I've read it...35? 40? 50? 100 for my memorization of it? I'm serious, this is a fic that trully fits the description 'straight to the heart with no detours' ~Me ^^;), followed by Katsu's "Ocean Trilogy". *sighs* Too bad I didn't find Acherontia Atropos until much later. *snaps fingers*
The above mentioned masterpieces still hold special places in my 1x2 obsessed heart and my first 1x2 fic was actually a bit 'modeled' after Yundah (Ocean Trilogy part 1). *blushes* Hey, I was a newbie! But since then I've wrote quite a bit of 1x2s, and you can find them here.
I'm telling you, 1x2 is for life. ^_~