It is no change from what it is now. No worse, no better. Players go on to TBC by simply staying where they are. Nothing happens.
Is there some reason it will be worse?
Blizzard rejected the idea of a “fresh start”, and dealing with the dozens of different situations players have, and creating a policy for each of them. This is an MMO. If players create a problem, that problem stays there. Blizzard doesn’t fix it.