I'm going to strongly disagree that dumbing down is really a good word for this. I understand your sentiment and, just to cite my bona fides, I moderate the Catalyst BT forums, have about 3/4 of the paper library (including TROs), multiple copies of Total Warfare (core rulebook 1) along with the other core books (including Interstellar Ops beta), and sometimes play a little MegaMek.
But! I really don't think straight up Battletech is all that suitable for the kind of game Harebrained wants to make, especially if I think back on my experiences with MegaMek and all its complexity. It's highly crunchy and oriented towards record-sheet tracking, many dice rolls, hex facing rules, and multiple levels of exceptions. This is an absolute blast for board game players, but it doesn't translate well to a media heavy turn based tactical game of the type they want to create. Even in turn based games, you want the core game loop to be easily understood and digested in a short period. Battletech's core loop is spread out and the structure of weapons and equipment exceptions makes it difficult to grok the essentials of what's going on and get back to understanding the wider tactical action.
To borrow from the various "rules levels" of Battletech, the squad game is one level of granularity too low to create the kind of game Harebrained wants. It's about the deep crunchiness of weapon location and systems management in a 'Mech rather than the tactical picture of lance movement and terrain. The board game has that, but the systems level stuff goes too deep to provide the right fun for this audience.
Now before you go back to claims of "dumbing down", I'm hardly advocating simplicity for simplicity's sake. I'm advocating simplicity in one place so that we can have complexity in another place. Maybe the core loop still engages weapons systems, but that the mechanics of those systems work differently so that the developers can abstract the math more easily, maintain clear "personality" in the weapons systems, and keep the emotional intensity of the gameplay up. Like they said, it's not a cover based game, but it is about huge walking tanks positioning themselves in the right places so they can bring the right weapons to bear for the greatest effect. Lasers vs Missiles vs Autocannons and tradeoffs in heat management can all still be in there, but work differently than the board game.
