Having at least 1x1 802.11ac that's capable of working in the 5050 to 5900 MHz band will be a huge feature improvement. Such as to connect to a 'modern' AP running in an 80 MHz channel.

There's tons of environments where 2.4 GHz is a CSMA hell of noise and the performance in a single 20 MHz channel will always be crap, and ranges/real world distances between AP and pi will be very limited because of the extreme noise in the 2.4 band.

Amazingly powerful hardware for the price these little things.