I bought it for half-off, and while I've been enjoying it, I do find myself occasionally wondering if I still didn't pay too much. I can't imagine what people who paid full price must feel, so I'll definitely nth waiting for a while. I expect you'll eventually be able to buy it for cheaper with the DLC/patch work packaged in as well: espionage was already mentioned, but their attempts at a planetary combat redesign were apparently introduced in beta 0.6 and almost immediately pulled due to being terrible (which contributed to the lackluster feel of planetary invasions right now), and the designer mode's "role" selection (capital, escort, assault, etc.) is apparently a half-baked remnant from their efforts to improve space combat. Getting governments back would be lovely, and is likely another planned future feature; right now, all government techs do is give you a few new modifiers like, say, +10% production, which is all sorts of dull when compared to previous versions (especially when it's been a core feature since, I think, OS/2). I do like the shipyards, though, as well as individual planet balancing for production/economy/research sliders. Even the latter has its own issues, though; even on its own, but especially when combined with adjacency bonuses, it tends to reward extensive specialization and punish generalization. That, however, is largely a game design question.
Oh, also, it vaguely irritates me that the Arceans, Torians, and even the Drath are MIA. I'm aware of story reasons for the first two, but I'm not sure that's a reason to exclude them even in sandbox mode.