Why not? All we would get rid of grinding up a powertech and a mercenary. At least Mercenaries can stop whining about being neglected. More flexibility, and another thing that bioware could profit on.
I mean seriously, just cause you leveled up everything under the sun, doesn't mean we all have your opinion. It would still be 8 fucntional classes, with 3 skill trees. Just mercs and vangaurds coudl swap between each other.
My merc is my only 50, so.....ya, that being said AC respecs would just ruin things.