Interesting mix.
Suikoden V has brilliant political writing but the gameplay is a snooze-fest.
Xenogears... the gameplay is less of a snooze, but it's probably worse, with a few stupid mechanics. It also has outstanding storytelling, though it's a very different style than S5.
Xenosaga tries for the same style of storytelling as Gears but does a way less good job of it, it spans three games and ends up a mess. However, the first two games actually had pretty fun battle systems (albeit one could rag on the pacing of both games in different ways).
Tales of the Abyss has a pretty stupid, anime tropeish plot, but I do like the two main characters which is a plus. Its gameplay is... a simple action RPG. I don't like those, some people do, and those who do generally like Abyss.
I know almost nothing about Dark Cloud 2, haven't seen it talked about much in RPG communities I hang out in.
I'd honestly encourage you to read people's opinions about the games and decide which to play based on that, but if you're just counting votes I'll throw one for Xenogears... I like it and S5 about equally but S5 is quite a niche game and as such a bit of a lost cause here.
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