Note: the CD set you're talking about is Final Fantasy Chronicles, and contains CT and FFIV. FFV and FFVI were on a different set, Final Fantasy Anthology. (Just went over to the game shelf to check.)
Other than that, I wasn't impressed with the final selection on the PSClassic either (I mean, Revelations: Persona? Whose idea was that? I've played the game, and it's deeply flawed to the point of being tedious and painful to play sometimes). They really should have put out versions focusing on specific game genres--an RPGClassic with all the Square and Enix releases of the era, Suikoden I and II, WildArms 1 and 2, Koudelka, Persona 2 (both of them), Star Ocean: the Second Story, the PSX-era Tales of games, etc. is something that I would at least consider buying, even though I already own legit PSX disc copies of most of those games.
Of course, it turned out that inside the cute plastic shell, there's an off-the-shelf ARM-based board running a lightly-modded version of PCSX, and people have already started to hack it. I give it a year at most before someone figures out how to hook up an external CD drive and make it play whatever you want.