Ehhh... That's what we discussed the whole time..... one wanted to have a customizable M&E with the difficulties the game offers and the other one wanted the player to adjust to the difficulty of the game the devs are giving and especially are giving to the feature. Ahh... well nevermind.
I don't think that this is such a huge problem. As Knot3D said you will be encouraged to use M&E on different positions. The M&E and KIM are only used while standing or crouching in the Blacklist demo too. With all the mobility you have, you aren't required to use the feature at the right time where every NPC is standing in range and at the right spot. You can move around and look when every mark turns red and execute. M&E utilizes the CAR system and you cannot use the CAR system on the ledge or on pipes. That's how the devs presented that feature. They more often executed when on the ground. There is only the instance in the Conviction demo where you execute two guys through a window but they are near by each other. The right utilizations of Sam's skills with the CAR system might be a strong point to limit it through the difficulty too and I do think a lot of people would understand this decision.