I think the assembled shell without cutouts is a plus. For me, the point of buying one of these is to be able to build exactly what I want in a camper without compromise. What I want doesn't quite exist in the market, especially in terms of the components used. It's a bummer to have to buy a camper only to then undergo the expense and effort of swapping out the components (for which you just paid) for the ones you wish were options in the first place (and have now paid for in addition to the camper price). One of the areas that is often a let-down on commercially-produced slide-in campers is windows, so having total control over selection/sourcing/sizing and location of windows is fantastic, especially for those of us who'd like to do some unique layouts and use the money saved from building our own camper to source higher-end windows than what you'd be able to option on a commercial unit.
BTW, any update on shipment arrival? Been holding off on a camper purchase until I see how these turn out! Very excited.