Perhaps there wasn't enough space structurally to increase the dining size? It is interesting, though, because I have to imagine there are a lot of folks flying LAX-other hub-INTL destination, meaning there will be plenty of folks who could use the club.
That said, it will be interesting to see who is actually aware of the dining room availability / functionality. My wife and I ran into one of her colleagues in the EWR Polaris lounge a few weeks back, and they had no idea they could order a whole meal until we told them. Same thing with my relatives - they were completely unaware and didn't even bother checking it out (I wasn't there to point it out
).