To me, if these guys are dangerous terrorists, then I don't see why the Israelis would release them in exchange for just Gilad Shalit. Gilad Shalit is not dangerous to Hamas. He's just some guy they kidnapped. Presumably, these terrorists Israel has locked up are there because they have either committed, or participated in the commission of, horrendous crimes, and there is reason to think they are still dangerous.
If, on the other hand, all the terrorists offered in exchange are not dangerous, as in, not really terrorists, then why are they locked up in the first place? Just for the purposes of prisoner exchanges? That seems pretty stupid - stop locking up prisoners to be used for prisoner exchanges, and you take away Hamas's reason to kidnap Israeli soldiers.
I understand there's some psychological benefit in doing anything you can to bring any Israeli soldier that falls into enemy hands home, but I think we can agree that a thousand terrorists seems excessive. It seems the height of foolish sentimentality to me to hold, as an absolute value, that you'll give in to terrorist demands to bring a soldier home. Again, assuming at least some of these guys have blood on their hands, I don't see how there is a net gain, even psychologically, in bringing home one soldier, who killed nobody, in exchange for a prisoner that killed twenty people at a pizzeria. If anything, soldiers accept certain risks (such as capture or death) that are not typically contemplated by restaurant patrons.
And, just additionally, if you're unwilling to negotiate with Hamas to bring peace to the region, because you don't negotiate with terrorists, then why the hell do you negotiate with terrorists to bring one soldier home? Especially when the terrorists only kidnapped the soldier so you would negotiate with them for the release of prisoners?