While I know this one is a foregone conclusion from the moment I saw the lineup, I'll stick up for Suikoden V since it was one of the games I nominated.

I feel the two areas where Suikoden V is better than Suikoden II is gameplay and dealing with political ideology.

Gameplay is largely a no-brainer here, Suikoden II has a really nice combat system and while it offers much more in terms of character customization, it's still barely a step up from FF/DQ IV in terms of depth whereas SV's gameplay has the skill system, larger selection of runes, party formation abilities, and a more conscious effort to make the playable cast members feel distinct from each other with unique skills and runes that work towards specific roles in combat that are more than just: Heavy Melee, Magic Knight, and Mage. Not to mention that SV just has a lot of fun characters to use, whereas SII is a title where I tend to play heavy on favorites because some units are just flat out more useful than others. In SV, I don't mind Georg being removed from my team because he's such a game breaker and it allows me to really use other team members, whereas I get annoyed in SII when I can't use both Viktor and Flik because I love both of them and they are pretty standout party members on top of that.

The actual duels in SV are some of the best, with more graphical variety, more duels in general, and a timer that makes it more hectic since you now no longer have all the time in the world to either decipher what their tell is or just quickly Google the answer. The fact more characters than just the MC gets a turn is really nice as well.

As has been mentioned, SV has the best War Battles in the series, being a simplistic RTS that uses the series standard Rock, Paper, Scissors mechanics whereas I feel SII has the worst in the series because the rules are poorly explained and the RNG factors in way too much. In SV, you actually have to learn how to flank troops or lead the enemy into ambushes all in real time which keeps you on your toes, whereas SII has too many instances where your high level unit suffers a devastating critical hit, from a units whose stats say they had no chance in winning.

The only area where I would agree that SII is better on the gameplay front is that SV is super easy, in a series that was always pretty easy to begin with. In fact it's the only entry in the series where you can finish off the final boss without ever taking damage if you bring the right people and use the right formation.

On the political ideology front, I appreciate the fact that we get to really explore the political faction element of a failing government, because this is usually the real cause of government's turning into despots. SII has some interesting politics going on, but it is really only with the City-States you get to see true political dysfunction. Highland is a typical evil empire with a power hungry King, his ax-crazy son, and even when the powers change to a moderate, they basically decide to continue the former evil people's policies because they've lost hope in lasting peace. Granted, supplement material proved that he was right in a way, but in a series where genocide is often frowned upon, even being right about everything doesn't make you morally right in this case.

Watching the Godwins and Barrows factions plot against each other and the Queendom is interesting, and it shows off the type of self-centered extremism that often permeates real governments. How much their rivalry plays out in the game's backstory adds several layers to the political issues that are hurting Falena. In essence, SII's politics can be summarized as the hero trying to get a squabbling group of kids to work together to beat a common bully, which in essence is kind of the plot of most of the series as SIII and IV don't really stray far from that formula, and even V has a lot of elements to it as well. SV's political narrative is akin to a a person with terminal cancer that they can't seem to get rid of and the plot being about trying to get rid of something they've dealt with for years that now has a real chance to kill the whole body once and for all. Even in the aftermath of SV, despite both factions losing a lot of their political clout, it's not like they are gone for good.

Granted, with all this said, Suikoden II is a fantastic entry in the series, but I feel SV is a worthy successor that's often overlooked.