Indeed. If you have an interest in Suikoden Tactics, you should at least try to buy and beat Suikoden IV. Not only does it make the story more understandible, but you also unlock new stuff by getting all 108 Stars. But if you just want to pick up and play ONE RPG, you should go for Suikoden 3. Here's my Suikoden IV review
http://www.mygamer.com/index.php?page=gameportal&id=243642
The thing about it is Suikoden 3 has a much more innovative battle system and character customization system, but the thing is you won't know what the hell is going on in the story unless you have played Suikoden 1 and 2...otherwise lots of the revelations have much less shock value.
As for FFT. The job system was excellent, in no small part due to the fact you could use all the skills from other job classes, like the Counter and Movement skills, that made the characters so damn customizable. The storyline was really, really great though, but you really can't put it together unless you play it a few times through, but it is lotsa politics and politicians, but it boils down to Delita quitting the Hotuken Knights after his sister dies, joining up with the Murond Glabados Church, assassinating a few of his superiors, arranging Larg's and Goltana's death, faking Orlandu's death to gain Olan's support, distributing the Holy Stones so that Ramza would end up killing all the Shrine Knights, leaving him as the undisputed King of Ivalice by marrying Ovelia. Anyway, Final Fantasy Tactics was released around 1997, in limited quantities, so it really didn't sell THAT well. Around 2000 or 2001, they rereleased it. But I don't think it's sold all that many copies. But I do agree, any game that has a word that resembles Fantasy will sell great.