While the independent story for this game is subpar, it fills in a lot of details to Suikoden IV (like why you fight so many fishmen in that game lol) and made the returning characters from IV actually memorable.
However, I really enjoyed learning the battle system in this game and the challenge and simply wish the game was a little longer and had even more optional challenges. Most of the time, tactics games are not too interesting to me because of how overly complicated they get--this is a nice balance for me, as you don't have to worry about building a character a right or wrong way and just level each up to see their strengths and weaknesses. This encouraged using the varied cast as opposed to building specific characters to get ridiculously broken, although the objectively inferior characters did get left behind. I really liked the sprites, enemies, actions (strictly Suikoden-themed; expansion of weapon runes and translation of the elemental runes for Tactics) and maps as opposed to the weird "running in place" sprites and actions (throw rock, what?) from Final Fantasy Tactics. The elemental tile system worked really well in relation to the Suikoverse Runes, and Sword of Magic was actually cool.
I would love to see another Tactics-style spin-off (and of course, Suikoden VI... RIP Suikoden) that further expands the lore without necessarily being a full-fledged 108 SoD game.