But the reason why they were hesitant to turn the bridge off, is because the Redverse will revert to falling apart again once the bridge is severed. Fauxlivia said earlier in the season that the Redverse has started to heal ever since the Bridge was created.
I don't think Fringe will permanently remove the Redverse from the story...we're too invested in the characters in that universe for them to just be forgotten. Plus the audience will know that the other universe is there...I believe a permanent removal isn't an option. But then again this is Fringe...so who knows.
Actually, Walter clearly said that closing the bridge will stop the healing, but won't cause any further damage to the red universe. ("It won't get better, but it won't get worse", or something along those lines ). So, it will still have problems, but it won't revert to falling apart.
Anyway, I agree that this universe is too important to be just gone permanently. Like you, I think it will pop up at some point ... but not anytime soon, or else what was the point ?