Things I liked:
1. The story. And not just the actual plotline itself, but the way it was told, too. It was crafted very well... the way it teased you made it very hard to put down the game. After all, there's more to a story than the content.
2. Character/graphics design. VERY nice art direction. George and Zerase's portrait and sprites were very cool. There were a ton of unique weapons, which I also liked. Admittedly though, rune spells were pretty damn lame, a step back in the series. For the most part I liked the monster design, though there should have been more variations/less buffed up repeats.
3. The voice acting. About time Suikoden got it. The voice acting, unlike tons of voice acted games, was VERY well done, fit the characters perfectly in almost every situation. Yeah, the only complaint with it though, is that it should have been done more often... there wasn't enough voice acting in the game, especially with such a talented cast, for sure.
4. War battles - seems like I'm alone in this one, but I think they're perfect the way they are. Not challenging enough to be a nuissance while playing, but a step up in difficulty from it's predecessors. The reward system was pretty cool, too.
5. Duels - 3 second time limit for options is perfect. They're still too easy, but more difficult and much cooler than before. In previous games the duels were basically a two characters fight but with worse graphics. Not the case here. The voicing enhances them very much too.
Things I didn't like:
1. Sound track. The soundtrack was good, don't get me wrong, but for a game that matched Suikoden II in almost everyway, the soundtrack was a letdown. Most tracks, while fitting enough, are honestly boring and repetetive (although there are a few gems, such as the "Imprisonment" and "Bitterness.") Suikoden II still has the best soundtrack in my opinion, it's the only suikoden OST I actually listen to outside of playing the game.
2. Difficulty. Ok, seriously, the game is way too easy... WAY too easy. Sure, you can use other characters instead of overpowered ones, but it doesn't help me that all of the coolest characters designs (killey, belcoot, zerase, jeane, etc) are ridiculously over powered. Not to mention the game forces you to use Zerase, Georg, Miakis, and other overpowered characters on more than one occassions. They should have included a hard mode, somewhat like Fire Emblem, I guess. Anything to give players the option to have a challenge in the game... finishing off a boss in one turn is just ridiculous.
3. Loading times. Apparenty I got a defective disc or something, since my game regularly lags anywhere form 10 seconds to a minute during such simple tasks as opening the main menu, but I hear they're still pretty bad in a normal game, too.
4. Killey's portrait. Ok so this is totally ridiculous and a small peeve but I HATE Killey's portrait art, it's absolutely TERRIBLE. SuikoII had it right. For such a cool characters, they sure knew how to make his torse look terrible, rofl.
5. Jeane's costume. So damn stupid, give her some clothes. Stop catering to a ridiculously horny fanbase.
6. Childerich was seriously a lame character, I have to admit. Seemed like a shameless Luca Blight clone to me, but less developed, worse design, and less importance. Oh well.
7. They really need some sort of cinema mode, or something, where you can view voice-acted cutscenes after beating the game, or something. I can't tell you how many times I've wanted to be able to view Galleon's recollection of the Godwin Invasion at my leisure.
8. Finally, the ending. They've pulled the revive trick not once, not twice, but THREE times now. It's just a little excessive and redundant. If they HAD to revive a character at the end, I would have prefered Lyon to not simply not die at all, and have someone more interesting revived, such as Sialeeds or Arshtat/Ferid. But eh, no game's perfect.
I love Suikoden V, it comes second on my favorite list (Would have tied II for first, but the Riou's ridiculously funny dialogue choices throughout the story really made the game on top of everything else, IMO.) If I had to rate it numerically, it'd probably be somewhere around 9, give or take.