Suikoden IV wasn't too bad...must say not the best game in the series, but boy did they screw up the original plot of Suikoden III. That was Konami's biggest mistake!
What the smurf are you talking about? S3 was great! GREAT! It was S4 they screwed up badly.

S3: original characters. New, interesting hero system. Very developed characters. Good story; couple of good plot twists. New battle system (not the best, but at least they tried). New, very interesting, very well done skill system. New world map and major battle system (again, not great, but they tried).

S4: A LOT OF SIDE STUFF (treasure hunting, etc). That's about all this game had. NO character development (unless you count Snowe, who was just irritating as hell, so I tend not to count Snowe), a plot that a 12-year-old could've put together with more sense, a horribly boring battle system (the S1 battle system was better). I give them credit for the world map, though (again, not great, but they tried).