I kinda like how design impacts the usability of a mech. I like not just choosing mech from its armour values and weapon loadout but also for how it handles, how my view from cockpit is and how good its torso twist rate and angle is.
That said I think some mechs have a bit too wacky cockpits. The Mauler comes to mind, though its perfectly possible to work around it. For the MKII I sort of like how the cockpit is limiting. with all those big guns on it I don't mind at all that its not as good at angling its cockpit down. Of course these things have to be factored into and against the assets other aspects and should impose a penalty that is not in some way offset by an advantage in another area.
/Merf - Senses another challenge for the mechlab to overcome