At a very high level, then if someone were to interpret the approach of Civ 5 being the spiritual successor to the previous Civ iterations, then I'd say no, BE is not the spiritual successor to AC, as it isn't named Alpha Centauri, doesn't have the Planetmind, fungus, mindworms, monoliths, Factions, Progenitors, etc.
However if someone were to take the approach of BE being in the same vein as previous games such as SMAC and Pandora in that they are all planetary sci-fi 4X TBS's, then I'd say yes, this is the spiritual successor to AC, Pandora, and any other games in the same vein.
Overall I am glad the developers are not just taking the same game and updating it, and that this is a new game (and from what I've read so far, this is the opinion I am forming on the subject). It should be interesting as more information is released over the next few months and we see how the game takes shape. Should be interesting!
D