In my opinion, the main issue is the price. The compromises aren’t that significant for most people, but Apple priced the Air too close to the Pro models. They wanted to position it as a thinner version of the Pro ("With the power of pro inside."), which limited how much cheaper they could make it. The problem is that the small price gap means the Pro ends up cannibalizing the Air’s sales. That’s what pushed me toward the Pro, why pay nearly the same price for less? Once you add the MagSafe battery, it basically costs the same as the Pro.