I would not buy a phone without a microSD slot, and the Nexus line fails by not including such an essential feature.
But, more important than that: Google definitely should put more pressure on manufacturers and carriers to keep the phones' OS updated for longer.
One persons essential features are another's rarely used amenities. Features such as microSD slots or removable batteries take space and as such they come with the trade-offs of added bulk or smaller battery. Fortunately unlike apple's iPhone family the android ecosystem is open and there are a plethora of devices out there to satisfy most peoples needs and budgets