Maybe you'd like the meta game more then, i.e. simulators where you can create pokemon with IVs and EVs exactly as you'd like and you just battle others. There is much more strategy in that than in the main series game.
I've probably played online Pokemon simulators before any of you guys have. I was a pretty good battler back in gen 3 (when the simulator of choice was Netbattle or RSbot), but gen 4 and gen 5 did not strike my fancy. There are too damn many Pokemon and the strategy space is just so much more confined. It used to be that you could feasibly prepare for every threat if you were smart, but now that is no longer possible and every now and then you'll come across that Pokemon that you were completely unprepared for.
(I get the impression that Gamefreak doesn't care about balance anymore either: things like the Stealth Rock damage formula, the absence of Rapid Spin analogs, Drizzle Politoed, ubiquitous Draco Meteor and Outrage, Normal types being comparatively useless, and so on. Those things made the metagame a lot less enjoyable. Plus the power creep in gen 5 is absolutely huge; I was pretty surprised when gen 3 OU staples like Swampert, Snorlax, and Zapdos dropped down to UU.)
Getting through the game is a piece of cake. A lot of fun, but a piece of cake. But the online simulators and the "extra-game" features on the newer games (like battle subway for Black and White) are quite strategically deep. The Battle Subway is especially tough because you actually have to breed for these perfect pokemon, which usually takes a lot of time and planning. But if your pokemon aren't fairly perfected, you're not gonna do that well at later levels.
I cannot afford to waste hours upon hours of time on Pokemon post-game content, and it just doesn't feel the same when you beat an AI.