Someone please correct me if I'm wrong, but I understand that it's not as simple as just reopening the old terminal for LoCos. When the new one was built, a full envrionmental impact assessment was avoided because the old terminal was closing. Reopening the old terminal would involve a lengthy planning process. Although I suppose it could be argued that is all the more reason to start looking at it now.
The check-in desks situation in the new terminal doesn't worry me unduly. My experience has been that the only flights that experience unacceptable queues for check-in are charter flights where everyone is checking in loads of baggage. The security gates situation is more worrying. At busy times, we already see three gates in operation. I fear what the queue to get through security will look like between 6am and 7:30am in Summer.