I don't think the check swing can be used with Classic (either system). I actually had a check swing with Boesch and they appealed to the 3B umpire and he called it a strike. That was something I've never seen. I've never actually got a check swing to be called a ball so far, even on balls out of the zone. I'm not sure if I was too late on it or not although I've only done it few times.
I've never stopped playing this game. I might not have played it as much as when I first got it but I'd still play at least a couple games a week and it's certainly harder to hit your spots. I'm certain of it. One issue I always seemed to have was that my fastball would only drift left on me with a right hander. Now I'm seeing it tail inside to RH batters. It's very noticeable imo.
I may be wrong on the double switch issue but I'm very happy with the pitch accuracy being tougher. I've hung a couple pitches in the middle of the plate and I would have NEVER done that pre-patch. It does seem as though the cpu hitters may swing at more stuff out of the zone. I've only played 2.5 games post patch but I think that was tweaked. My offense has sucked post patch too. I have a feeling that both offenses may have been toned down just a little. Too hard to tell from 2.5 games as I may just be in a rut (lost 5 of 6). I need to play more but tonight I have to watch "It's Complicated" with the wife.