Quoting GeneralsGentlemen,
Multiplayer LAN would be a great feature to have but unfortunately every feature and change we make has an opportunity cost, especially as our team is quite small. It's on the list so it may happen at some point, but it's not a priority. I'm guessing only ~1% of the player base would find it useful.
That is the same kind of thinking when the game came out, that nobody plays SP games...when in reality, the vast majority of the players only play SP with some skirmish games.
There are LOTS of people out there who play LAN games, as well I am sure you know, LAN cafes that cater to people looking to play on the LAN.
That said, I don't think it should take priority over fixing bugs or anything like that, but, it will be a welcomed feature. It doesn't have to be pretty, people can just enter the IP of the hosting computer, much the same way they do in Supreme Commander.