I stopped getting TW games after RTW. Is this unit overlap effective in the later games? In STW (not sure about MTW), units got a penalty if they were crammed together - "no room to fight". The STW strategy guide lists this as a defensive penalty only.

If S2TW goes back to a stronger rock-paper-scissors combat model, such an overlapping feature might disrupt that scheme. Combining rock and paper lessens the importance of maneuver as rock to does not have to move to protect paper when scissors attacks. If the counter to that is that scissors combines with paper, it seems like this reducing combat to forming combinations that lead to no vulnerabilities and combat becomes a bore-fest. Maybe I'm missing the point or not seeing the possibilities correctly, so that is where you are going to have to educate me on what the proposal would do to make the combat more interesting.