Romantic as a side or main plot

There are essentially two forms of romance in anime genre speaking: there are those where romance is a main plot or supporting main plot (many shoujo series and the rather hated harem genres) and then when it is a secondary side plot (Evangelion and DBZ have romance in minor pieces but Eva stresses romance more than DBZ).

I concluded that a way to tell whether romance is a main or side plot is this: Romance in the main plot will emphasize main two characters having a strong and often childhood connection and emphasizes music in the opening and closing credits to display it. Tower of Druaga is romantic in the main plot. Another Gonzo title, Ragnarok the Animation, is a romance in the main plot but some may think with its action genre that it will be a side plot. Fullmetal Alchemist's Edward Elric is childhood friends with Winry Rockbell. Breaking the sexy dumb blonde stereotype, Winry is sexy, smart, and she kicks ass. Alchemist has romance in the side plot type. What's cooler

That being said, is Xamdou romantic as a side plot or a main plot/supporting main plot?

i think its half and half. the story appears to be following how akiyuki is discovering himself through his hiruko, and when haru goes along for the ride, it kinda shows how love prevails (kind of???)

What I forgot to have posted is "What's cooler is that Vic Mignogna and Caitlin Glass, the dub voices for Ed and Winry respectively, like this pairing too. That is, the voices of the lead male and lead female in the dub.

I agree. The romance is a large factor in the motivations and ultimately the development of several characters beside Akiyuki and Haru, but it isn't the only factor. And its not like Eureka Seven where the relationship is constantly shown as the key stone for the characters, as Akiyuki and Haru have actually spent more time in the series apart dealing with their own issues other then having traditional romantic problems like admitting their feelings for one another or all problems set to try to keep them apart.

The show deals more with the idea of knowing yourself and being aware of your relationship with others then it does pure romance. Its there but it isn't the main theme of the show or as heavily featured as other shows like the aforementioned Eureka 7.