Well, the two pilots thing actually makes sense... maybe...
Essentially, the mechs themselves need to be monitored, maintained, and piloted. Simultaniously. Otherwise the mech would tear itself apart trying to do stuff.
From the clips I've seen, this is more-or-less actually stated in the series.
-And was theorized earlier to be the reason behind dual-pilots in Pacific-Rim... aside from left-brain/right-brain BS.
A irl analogy would be early radar-equiped interceptors having a WSO in the backseat whose exclusive job was to watch the scope, navigate, and anticipate all electronic warfare/missile threats while also dealing with squadie-chatter.
-Although in the case of a Franxx, this appears to be what the person in front usually does... with emergency-controls...