I personally have yet to see a single mech game that did not score in the eh... ok... ranges, largely because the mech games in themselves tend to be technical, which clearly is not for everyone. Even Mechwarrior 2 just got an "Ah, it is all right, but you have to think about what you are doing" score.
I still see most if not all of the elements of the previous Front Mission titles in evolved, minus the turn based element. Wanzers despite the turn based thing, are actually quite fast, as you can see in all the cut-scenes in FM 1-5. I particularly liked the opening movie in Front Mission 4 with the rapid sting attack by the Zaphtran forces on the german base, that was bad ass. I feel that Evolved will try to bring that experience to the player, rather than them having to imagine that they are soaring around, doing a triple spin to spike someone with a pile, or rocketing on a JATO launch system into combat. Also, I have a feeling leveling is still going to be a critical part (which I hate actually as it rewards the person with the most free time, not the most skill) so I don't feel the play style shift will be too dramatically different.
Also, slow? Wanzers have effing rollerblades with rockets as standard moving equipment. They are the wile-e-coyote of mechs.