Well most of the people [especially those, who didn't preorder] think that EWoM is the successor of MoM. Do you really think that those people are expecting to have an RTS or WEGO style combat system?
No they wouldn't be - they wouldn't expect anything at all in particular. Most of the potential buyers have never heard of Elemental, beyond maybe the fact that it is a game in development, and will in all likelihood not hear much about it until much closer to release when actual previews and reviews start coming out. If they haven't ever really even heard of the game, then they probably don't "think that EWoM is the successor of MoM." And when they read those previews and reviews, they will learn what to expect from it.
Not to mention, I have been a TBS junkie since I started playing video games in ~1994ish. Before MoM even came out. I had never heard about MoM until our friends at Stardock announced that they were working on a spiritual successor to MoM 2 or 3 years ago. So even some of the most avid TBS gamers have never heard of MoM, so it wouldn't be too crazy an assumption that a sizeable fraction of more normal people who enjoy TBS games haven't heard of it either, let alone played it.
I think they just wanted to make it as moddable as possible, and chose the "least controversial" (because people who buy Elemental expect a TBS game, so it's logical that the combat is turn-based too) system as the standard one.
But that doesn't make sense. People who buy Total War games expect a TBS game, but it does not have turn-based combat. Sure, by now there have been enough Total War games that most people who are likely to buy one would either know from experience that Total War uses RTS combat, or they'd have heard through the grapevine. But what about the first installations of the series?
And far more importantly, anyone who buys a game without reading about it at all deserves whatever it is they get if it turns out they thought the game would be different than it is. People expect what is advertised about a game, not the first association they make in their heads when they see the genre. Not to mention that nowadays the inside of the box cover of most games displays major game features quite prominently. People who don't know anything about a game don't expect anything about it; people who have done their research know what to expect.
...This thread has gone off topic. But I suppose it has gotten to the stage where it's too unwieldy to be very productive anyway, and I think most topics of relevant discussion have been more or less exhausted so I don't feel too bad for contributing to the derailing of yet another dev post. 