Before playing it, having only seen the trailer, I called P4 'P3.5: Yellow Remix' because of how similar it looks to its much loved prequel. I pointed out that the only changes made to the dungeons seemed to be the insertion of doors (awe inspiring stuff) and, aside from there being ONE new floating type of shadow visible in dungeons, I wasn't exactly wrong. I wasn't right, but I wasn't far off.
Don't get me wrong, though - P4 is an improvement in many respects. However, it's more a case of minor touch-ups that improve the experience considerably, such as the ability to see what spells do outside of battle and not having to guess, rather than a complete revamp. But, in truth, I didn't want a new experience with P4, I wanted the same experience with fixes made to everything I found to be troublesome, and they did correct a lot of issues.
To start with, relationships no longer reverse if you don't see one your social links for two months. That was a very serious problem for me with P3 because, on the first playthrough in particular, I found myself trying to do too much, often starting social links and then leaving them to focus on others. And, moving on to another social link fix, there's no longer a danger of female social links reversing on you because of jealousy, which was yet another serious issue for me because I wanted to level up more than one girl beyond a certain point without first having to get one to the dizzy heights of rank 10. The ability to simply pick your girlfriend this time around is a huge plus.
The improvements didn't stop there, either. Playable characters now become more useful in battle as you become closer to them, making the playable character social links the most important. The ability for other characters to take a mortal blow for the MC, preventing game over where possible, is priceless, and it makes those social links seem special.
...But, whether because of a lack of effort or ideas, the actual social link scenes are rather poor this time around. I've gotten Yosuke to rank 10 - my first so far - and I was bored of the social links with him after the first few times. He simply repeated the same emo rubbish in every scene, going on about Saki-senpai (the use of Japanese suffixes in English has caused me to do so!), a girl he barely knew, thinking about if she was watching him from heaven. I found myself wishing she'd struck him with a bolt of lightning from heaven...
Not all of them are poor - the nurse and drama club links seem interesting - but the majority I've seen so far have been too short and too dull to impress. What I said about Yosuke also goes for Chie and Yukiko, which is an awful shame when there could've been some great backstories thrown in. Should I care about Chie having a wimpy friend who liked Yukiko more than her? Should I care about Yukiko learning to cook? The answer is no.
In a way, the games plot itself, or rather the way the game is structured, is what caused the issues I have with the social links. Before you get to use the characters in P4, you learn their darkest secrets, seeing what makes their darker sides tick. And, after seeing the most interesting aspects of each character from the get-go, there's little of interest remaining to be shown in social links involving them. That's why their social links seem so...forced, repeating dialogue over and over instead of adding depth to the cast.
Talking of the structure of the game, I prefer going to different dungeons instead of just climbing one endless tower of doom. It's a deceptive change since all that's really changed this time around is the dungeon layout and floor count changing when you go into new dungeons instead of when you reached a new tower block. But it works far better in P4, with the monthly story events getting tied into the dungeon this time around and not not occurring at a random location in the real world.
...Sadly, however, for all the small gameplay corrections Atlus made, ranging from the ability to use the square button to move around the game world in seconds, they seem to have failed to improve the one aspect of P3 that ultimately resulted in me dropping it after 70 hours - the story. Both P3 and P4 start out great, presenting a dark mystery that kept me gripped to my TV...but, like P3's plot before it, the story of P4 seems to be no more than an excuse for the game to last as long as is needed for the social links and the statistics of the main character to rank up. Each month a character gets introduced, yet there's never any real plot advancement. I've gone through something like 4 months of the game and, aside from new characters, nothing has changed from the start. I get the feeling it's going to go the way of P3; seemingly building up to something epic and then becoming pathetic once the fog (no pun intended) clears, revealing a poor story that had been procted by lots of mystery. Since I've seen no indication of the story walking a different path this time around, I'm not holding my breath in the hope of everything coming together in a satisfying manner.
Atlus also failed to fix the other issue that resulted in me dropping P3 - the evil known as skill inheritance. As all P3 players know, fusion became hell towards the end because getting the few skills you wanted a new persona to have, out of the sometimes 20+ available, often took hours because the skill inheritance system is a random one. Rather than simply allowing players to pick which skills they want to keep, Atlus made it needlessly messy by forcing players to refresh again and again in the hope of getting lucky. Why they made it like that I don't know because it adds nothing to the experience outside of pure frustration. Having patience and luck isn't the same as having skill, so why not just make life easier, and more enjoyable?
I don't know if I'll make it to the end of P4. When I was playing P3 I'm sure I thought, 32-35 hours in, that I'd be playing it for over 100 hours because it was so addictive. I feel the same way about P4 right now. The real test will be when the wheels start to come off of a story hanging on a huge mystery and the big, end-game fusions come into sight. Right now I can see myself playing it for 10 hours+ in a row if I have time/don't feel the need to sleep, and I truly hope I feel the same way whwn I near the 70 hour mark this time around.
Edit: Oh, I almost forgot to mention the biggest fix Atlus made - the ability to control the entire party. The AI in P3 was retarded more often than not, so it's great Arlus saw sense and did the smart thing, preventing players from dying because of stupidity of the AI.