I really liked when Platinum and HGSS first started to overlap. Seeker and Uxie really made my deck run smoothly, and Poke Healer + was still around to help heal. There were strong basics, but they weren't as overpowered as the new EX basics are.
I was messing people up with a Giratina Lv X deck combined with Miasma Valley and Team Rocket's Trickery. I'd get Final Wish Jirachi down ASAP, play Team Rocket's Trickery to thin my opponent's hand early on, and by the time my Giratina leveled up, they'd only be able to get one or two hits in before their hand was down to zero. Then they'd have to decide to play whatever they drew their turn, or save it to use for an attack. The look on their faces as I removed what damage they were able to do with a double Poke Healer made my win that much more satisfying.
I can still beat most current decks I encounter with it, or at the very least, make them work really hard for their win. Otherwise, when I'm playing only with what's current, once my opponent benches his third Deoxys EX, I just want to flip the table and walk away. Ignoring how expensive the cards are, I can't bring myself to running something made entirely of EX cards. I feel a lot of the skill has been removed from the game. That's not to say it's entirely gone, but when my old deck was legal, tournaments were challenging and rewarding at the same time. If I lost, the game was close, and I only had one card in my deck that cost more than $30 (Uxie Lv X, $80 before it was rotated out XD). Now when I play even just casually, lasting more than five turns is a milestone event.