I think the improvement to the terminal is very much needed.
I have used LBA quite a bit over the years and was last there in 2022. It remains a poor experience at peak times; long queues, struggling to find somewhere to sit and eat and very little in the way of glass to promote views and space. For that reason, if I can't go from Teesside, I will always chose NCL over LBA.
For balance, I was in NCL in the summer of peak afternoon departure and the experience was unusually pretty much the same, except you could see outside. The family ended up sitting on the floor to have a drink and sandwich whilst the echo of noise was like being in a swimming baths.
All that said, the departure point comes second to price and convenience and to contradict my points above, I have a future LBA booking planned for the simple reason Jet2 offered a daytime flight to the Canaries when NCL didn't....
Terminal investment is needed across the board really.....