I know most people want to get their alts to max level to raid and this change is welcome for them.
For a small minority that wants to take it slowly, explore the zones, do quests, some roleplay I think it would be great to allow additional Wrath accounts without additional subscription. To prevent server overload with the amount of created characters these additional accounts can have character limit of 3-5 or the total limit of Wrath characters can be shared between all Wrath accounts. These additional Wrath accounts could be activated with an one-off fee. I know that I can create additional WOW accounts but paying 2 or 3 subscriptions for fresh start in Wrath is not sustainable.