An excellent list, nothing terribly important "left out", although I would have mentioned unit building in your shoes, but points 5, 6, and 9 were, at least to me, if I may say so, either underspecific or suboptimally worded.
5. Tactical Battles. I think that you should make clear that you want to ensure that it is not the generation and visualization of tactical combat which is the priority, but a deep and rich combat system which will enable and/or require a player to think and make choices and gets her "hooked". The tactical battles will be exciting because the combat system is not a simple "more numbers is better" gig like in other successful TBS series, such as CivIV.
6. Civ Building is fun: You have left nothing out, and you have indicated that there might be debates about what concrete elements might be "fun" for individual players, but you should say something about overall thoughts on "funness". I propose a postulate, call it F: The precondition for FUN (that is: this is not an exhaustive description of everything which is fun, but, I claim, nothing which is fun *in a TBS setting* can avoid it) is a multitude of strategic choices; in other words, if there is only *one (feasible, competitively efficient) way* to do something, it is by definition a "no-brainer", and a strategy game full of no-brainers is no-fun. Make sure that there are as many ways of building your empire as possible, as many true choices as possible, to avoid no-brainers.
You should also mention here that you will want to be avoiding "mistakes" or pitfalls from the past. Such pitfalls include suboptimalities from your own products (research in GC2; unit building in GC2; planet building in GC2) as well as in other successful landmark games (e.g. cities in Civilization could only hold one of each type of building, e.g. one forge or one temple, and so each city came soon to resemble all other cities...). Make it clear that the player will have freedom to do what she wants (e.g. stuff a city full of temples if that's her desire) and still have feasible choices.
9. Magic Battles: It is not clear from your post how crazy magic battles will not be mopping up. It is not clear from that post how you plan to counter End Game Tedium, since having fun magic at your disposal will only counter that the first two or three games until the novelty wears off. Why is magic so much more exciting than the other stuff we will be doing the length of the early and mid-game? "Mopping up" takes place when my strategic advantage is unquestionable, yet I am unable to fulfill a victory condition for another X number of turns, where X represents a number of turns during which nothing challenging takes place. Why will crazy magic battles be challenging to a player if her strategic advantage is already secured?