Personally, yes I'm disappointed, very much so.
As others have said, I assume the small trunk is due to a very large rear seat area. We will have to see how roomy it feels when they are reviewed.
You cannot simply attribute the lack of cargo capacity to the 3 having a trunk versus a hatchback. This car is bigger on the outside than other cars that are smaller, yet have larger trunks. Chevrolet Cruze sedan and VW Jetta come to mind.
It's been drilled into us that EVs have much superior packaging than ICE vehicles, so actually falling in line and being very average in cargo capacity compared to similar sized ICEs leaves me disappointed.
I have a family of 4, and we like to take road trips. Long weekends, and, one week vacations. Had the Model 3 come with around 18 cu ft of combined cargo capacity, it would have been perfectly sized for the 4 of us, our 3 suitcases, and a few soft bags. Based on pictures of the frunk which appears to be 2-3 cu ft, the trunk will be 11 cu ft or so. That's a lot less room for beach toys in the summer, gifts at Christmas family gatherings, and pans of stuffing and pumpkin pie for Thanksgiving dinner at grandma's house.
It's definitely making me reconsider the Bolt with 16.9 cu ft.