They dont need to separate the queues. You can also get gear to be strong in your pvp bracket.
Dont joint a lvl 10-19 bg at lvl 10 and compain about the lvl 19 who 2 shot you. You also have the option to seek gear before you go into the bg, just as you have the option to level to 19 (or closer to it) before you join.
All twinking is is being as geared as possible for your level. Should we separate people with full pvp gear at max level to queue only vs others with full pvp gear? Then what happenes to those who have pvp gear with a few pve bis added in?
They put the time in and got geared. You have that option as well. And there is also counterplay to it. You can CC them and dot them and kite them, etc.
Original Blizzard wotlk team knew better. They separated the queue for good reasons. While most twinks stopped playing, most because they couldnt stomp other players anymore and others because of the resulting low activity, the overall leveling battleground quality and activity went up by a significant amount.
Of course the twinks were against it, back in the day same as today. However, the decision to remove twinks from the queue revitalized the battleground activity and resulted in more new players trying and actually enjoying battleground pvp.