Developing content before having finalized the structure of gameplay is tantamount to painting the insulation before putting up the walls of a house. So far, Alex has used a very logical (and time-optimal) sequence to developing Starfarer, even if it means less up-front enjoyment for beta players, but this is why we pay only half the price. If anything, we should support Alex in persevering with this sensible development plan, because it means less redoing and reprogramming, and ultimately a faster release of a final product.
Think of it this way. The more time Alex spends on structural and gameplay dynamics for Starfarer, the more robust the game will be. There is a lot of modding talent out there, and since the rate of content consumption is always significantly faster than the rate of content development, you really want as robust a game as possible, as this will enable the modding community to produce better content and enhance replayability beyond the standard content that is delivered with the final version of Starfarer.
Plus, content is relatively easy to develop once everything else is in place. Good gameplay, on the other hand, is extremely hard to find and rarely emphasized in today's market of high production value and eye candy. Starfarer is one of the few titles out there which seems to have its priorities in the right place. We would do well to encourage Alex to stay his course!