I thought pulling an Ash meant going into a gym battle and using exclusively pokemon that are weak against the opposing pokemon. Before I clicked on the topic, of course.
Anyway, I usually don't rotate. However, in White 2, I followed my own rule to not catch more than one pokemon for my team per badge. That means I had my 6th pokemon by gym 6. That slot did change quite a bit tough, as I had a tough time settling for a flying type. I had a Pidove purely as a flying slave, then something I don't remember before finally deciding to go back to Castelia and get myself a Zubat, which stayed throughout the rest of the game.
On that note, the one pokemon per badge rule works really well. I always had the exact level of the current gym leader's strongest mon and never had to grind. In fact, after victory road, I was slightly overleveled without trying.
I don't watch the anime on a regular basis, but stuff like Pikachu against Snivy(yes, I know Pikachu only lost because of Zekrom) and the first Unova gym battle tends to stick to my head too much. The newer episodes are different. My bad.