Well, the two pilots thing actually makes sense... maybe...

Essentially, the mechs themselves need to be monitored, maintained, [i]and[/i] 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...