Ultimately naval battles was never part of any promise made by the NW devs afaik, the props are being added for the benefit of the community. I think they delivered on their product with the exception of 250+ players thanks to a TW decision. As for value; I have seen plenty of inferior and less satisfying games being sold on steam for roughly 10 - 20 dollars. In any case 10 dollars will get you lunch.
Value is really a concept for the eye of the beholder, I think FSE can safely say they met most of their community's reasonable expectations. There will always be some people who do not enjoy a product or get bored of it eventually however but in terms of what constitutes value, if enough people are willing to buy the product (ie: there is sufficient demand at the given price) then the product has value.
If I am unsure of a products value to me (and I often am) then I tend to hold off from purchasing and either wait for the special deals or watch gameplay videos and reviews or look for product criticism and feedback online.
