Never been to Nashville but have heard good things. Having said that I'm not sure you can make a realistic comparison between the two. Taking a quick look on google Nashville although similar in population to Boston itself is 500 square miles to the 48 of Boston. It also has a CSA of just under 2M vs the 8M of the Boston region. The point being in a spread out city with plenty of available land you can do certain things that aren't possible in a more crowded place. On the flip side transit is never a priority in these places. Nashville seems to me to be comparable to Atlanta, Charlotte, Houston, etc - sprawling cities with cheap land. Boston is more like DC, SF, etc. Lots of people in a compact space. For whatever its shortcomings the Seaport is a product of what gets built when constricted by high cost of land acquisition plus a hard ceiling on how high you can build. If downtown Nashville isn't affected by these two factors, the comparisons are tough to make IMHO.