Finally! I had to wait a week just to reply to this thread. I've never experienced any forum like this before where the admin opens the registration for a limited time only when he's around. (Which is understandable to keep out those spammers, but still...)
Anyways, back to the topic at hand. It's true that some J-pop songs do not correlate with some of their shows but I think most of the songs actually do relate with the shows. The animators make the openings based on the songs.
Example: Black Cat's "Hana no Daia" (Diamond Flower)
The beginning, yes, it always takes place
under the ultramarine blue sky
Making a commitment,
now, I walk along
Yah, in the desert, alight in gold (the burning wind)
Searching for a diamond flower (I continue to wander)
Now, I'm living my life for someone,
for the first time
Explains the main character's change from being an assassin to being a Sweeper. Also, his relationship with the Sweeper who changed him in the first place.
In my opinion, I think having an actual song in the OP could work in English. If an artist wants to promote his/her work, why not? (bleh) 4Kids' OP for Yu-Gi-Oh 5D is having some people actually want a full song just from hearing it since it doesn't say "Yu-gi-oh" repeatedly in it. Of course, it's always been in Western handling of cartoons to have songs just be theme songs. But, why not take a risk one of these days? (Early 4kids Poke'mon days were also an exception where they did record full songs to their openings and are still memorable to some people.)
The Japanese cartoon, Hanada Shounen-shi actually used Backstreet Boys' "The One" in its opening. Those who watched the series said that the song actually related with the cartoon, even if it's in English. The live action Japanese version of Hana Kimi used Avril Lavigne's "Girlfriend".
I'm interested in seeing a 1:30 English made OP one day out of 3-4 min song... Huntik probably came close if it didn't repeat "Huntik" a lot, but the song itself isn't so bad either.