I've always believed there is diversity in classes depending on the player behind the toon and their style of play with the abilities and skills given.
I believed this in WoW way before there were any adjustments made to allow for class diversity. (i.e. ur a drood u can't tank lolz )
So, that said I'm sure that if Bioware gives the trooper the tools you will be able to use them as a tank. If they don't and there's a backlash then I'm sure they will eventually fix it. That's just the way things happen in an MMO. Each class in WoW had their talent points refunded multiple times because of major changes to abilities. I wouldn't be surprised to see something similar happen in TOR's future. I wouldn't expect it right away, but as Bioware tweaks the classes and adjusts class abilities I wouldn't be shocked to see it not just with the Trooper class but with the others as well.
"You'll find that many of the truths we cling to depend greatly on our own point of view."