Okay...some quick impressions:
***Please bear in mind these are all on DEFAULT to allow for the most fair comparison. Some improvements/changes may be possible with slider tweaks***
-AI aggression: Mixed bag. I'm a bit disappointed, actually. First, let me say it IS CLEARLY IMPROVED...lol. Just wanted to say that so nobody thinks it didn't get addressed...it did. The IE is fixed, but the results are minimal overall. Guys will take slightly more pitches, but you still have to dance on the edges.
Occassionally the AI will take a pitch a bit more in the zone, but it still needs to be close to the edge. I grooved several 3-0 fastballs and they swung every time still. I even loaded the bases and tried it (I mean, a mediocre hitter (and most very good hitters, to boot) won't be swinging 3-0 no matter WHERE you put it, but no-go. AI hit into a pop-out.
They will take a few pitches more over the plate though. If you're behind in the count and throw it to their cold zone, they'll likely hold off. This is both blessing and curse though as it's clear (to me, at least) that the AI is WAY too tied to their hot/cold zones.
In the end, it's improved, but likely not the game saver some might have been hoping for. If you were just wanting a slight tweak and were already enjoying the game for the most part, then you should be pleased, however.
-OF play: This is the biggest improvement I noticed. MUCH less herky-jerky and more fluid paths to the ball. There is still that annoying slow down and it can negatively impact a play still, but the fact that the twitchy play has been mostly eliminated is a HUGE plus. Well done, overall on this one.
-1B Glitch: Can't really comment on this as I never had this problem, not once. Needless to say, I still had no troubles post-patch if that helps anyone...lol.
-Batting Stance Snap-Back: GREATLY reduced. The transition still has a very slight hitch, but nothing like it was pre-patch. This was a pleasant surprise.
-Pitching accuracy: I noticed people saying (for the PS3 version) that there was a more realistic degree of variance. I don't see it. Either it didn't make it's way to PC or it's too small for me to tell. Pitches still go where you want on default control. I haven't tried it with release timing on post-patch. This should be a no-brainer to add though, if you're looking for more challenging pitching regardless of the patch, IMO.
-Animations: Less instances of jerky animations overall, it seems. Obviouslt the issues with base animations aren't going anywhere, but some of the transitions seem better and they seem to have toned down the opportunity for you to see guys doing dumb stuff.
Overall, the early returns are mixed. It's clearly a more playable than before (particularly the OF), but the real test will be if we can get some good sliders for the new AI aggression. Hopefully with good sliders, the difference will be more pronounced. As I said, this was all on DEFAULT so it's not time to hit the panic button. I was just personally underwhelmed with the AI agression tweak is all.
Didn't have a chance to dive into Franchise Mode and check any of that out, sorry. I'll leave more impressions (perhaps slider ideas too, if no one gets to that first) as I come accross stuff.
***Again, FINAL DISCLAIMER...lol...these are INITIAL impressions. Not definitive or meant to be anything other than potentially informative.
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EDIT: Wireless 360 controller seems 100% good to go now. My settings actually save for classic/zone hitting! Good stuff.
EDIT #2: A small thing, but important (at least to me) the fans now cheer for the right team now. Pre-patch, there were times when they would mix up and cheer for the road team making a good play and boo the home team for making a good play. This hasn't happened at all since the patch.
As I said, it's minor...but something I noticed.