Interesting! I would have never thought you the kind of person who would tire of regular Pokemon gameplay. As for me, after I beat the storyline, I usually go into "collection mode": I try to get all the items, Pokemon, etc. I actually did this in Platinum (my most complete game to date) and I have to say I felt quite satisfied when everything was finally done.
I am certainly with you as far as trading goes: I have to say that is one of the most fun aspects of the games, whether locally or over Wi-Fi. I just have problems coming up with enough trading material to maintain the ability to frequently exchange Pokemon with other people. Most people are here looking for event or legendary Pokemon, which I of course have limited numbers of, if at all. Once I have traded away what I possess, the only real source of fresh, new Pokemon I have is the GTS (and you know how that can go). And I do not clone my Pokemon, so it turns into a bit of a self-perpetuating scenario: I simply do not have enough rare or unusual Pokemon to go around.