I will tell you.
First, FreeSpace 3 will most likely not be made by Volition, but by another company that Interplay will contact once they find that another FreeSpace title might be enough to bring them out of bankruptcy. Since Volition struck a deal with THQ, and abandoned Interplay, there is probably a very small chance that Volition will get the intellectual property rights to be able to make the game and make money from it (legally, at least). If there's no money in it, then it simply won't be made. There's more money in it if Interplay goes and strikes a deal with, say, Derek Smrat.
Assume Derek Smrat or another person gets a hold of the IP and decides to make another FreeSpace title. They'll have their own ideas and their own convictions as to where the storyline will go. They'll turn FreeSpace into something else; if Derek Smrat got rights to make it, he expressed that he'd make his own universe and he'd be making it completely different. In fact, he said he'd go for his "universe exploration" design rather than the campaign and linear storyline approach FreeSpace takes. This will be like the prequel trilogy of Star Wars: canon crap. I personally wouldn't want canon crap.
Even if Volition got the license, I have to say FreeSpace 3 still wouldn't be great. Despite Volition knowing where the storyline will go and what they'll want to do with it, and being familiar with the universe and so being able to make a liable continuation of the storyline - It will not live up to our expectations. Personally, I envision any FreeSpace 3 as the ultimate gaming experience; the pinnacle of human understanding. But whatever it is, it won't be that. No matter how good it is, it just won't be as good as I, and undoubtedly many other people, expect it to be. We all think FreeSpace 3, whatever it is, will be unbelievable. But it won't be. It'll be a disappointment (unless it is mind-blowingly good).
Additionally, someone from Volition did actually say that if another FreeSpace title was released, it would most certainly be on the console, because it was "the future of the gaming scene" or something along those lines. Can you imagine FreeSpace on the XBox 360? Hell, can you imagine people playing it on their mobile phones? That would be wrong. A FreeSpace title will have to conform to the modern gaming tastes (or else it won't make any money). Do you understand what this means? It means it'll be on every console out there and there'll be stripped down versions of FS3 to play on your mobile phone or on your Nintendo DS or whatever. That means modding becomes impossible - You can't mod Halo 3, can you? You can't mod anything on a console. One of the most important parts of FreeSpace was how it was so moddable. Without the moddability of FS3, this forum would be long gone back in '02.
Also, FreeSpace 3 is made, everything we hold dear right now will be changed. Whether it's for the better or for the worse, it doesn't really matter. It will be such a big change that the entire FreeSpace community will be unrecognizable. To give a comparison, I'd have to say that it's like modern day humanity coming into contact with an advanced alien civilization - Whatever they do, whether they wage war or decide to give us hybrid cars that actually work, everything on Earth will be changed completely.
And not only that, everything from Machina Terra to Inferno to Black Water Operations to Derelict will become obsolete. Bye bye. They're all redundant now. They are not viable continuations to the FreeSpace storyline, now they're just a bunch of alternate events that could have been FreeSpace 3 - but failed. Even if they don't die like that, the motivation to finish old projects will be lost. Everyone will want to play the third title - Which would, seeing as it probably will be on a console, won't be moddable.
FreeSpace 3 will be the death warrant of the FreeSpace saga. Sure, it'll boost its popularity for a few months, but after that, we'll become a skeleton of what we are now.
