Wasn't the MacBook air supposed to be the ultra-thin option for people who used their computer for checking facebook at Starbucks and the regular MacBook line the people who needed are a fast computer with a long battery life for serious work?.
IMO, a few extra hundred grams is nothing once you go for a 15.4-inch format because I would either carry it on my back in a backpack which contains several things that weigh a few hundred gram to begin with or because I would have it placed in front of me on a table.
(I am pretty happy with my lenovo T line laptop. I is reasonable fast and has survived some water in the keyboard so far. Only minus is the trackpad).