Should rooms be designed to minimize waste of sheet goods?
If your objective is to optimize the product you receive (the completed house) vs the cost you pay for it by sizing to use full sheets of material -- forget it. The cost of all materials combined doesn't strongly dominate the cost of the project; they'll often sum to around half of the project cost. The panelized materials such as plywood or OSB sheathing, subfloor, and roof deck, and the drywall used throughout, are a small fraction of the project cost. Sizing the project to use whole sheets might literally save dollars or even tens of dollars per room. Other materials such as paint and concrete effectively come in bulk. Still others like electrical wire, drywall joint compound, or roofing shingles can't be reasonably estimated to ensure optimal use of each roll or box anyway. Basically the only thing where standard sizing matters is height: spec most of your rooms to have nominal 8 foot or 9 foot ceilings so that the builder can use off-the-shelf 92-5/8 or 104-5/8 studs. That makes the walls just the right height to fit 4 foot wide drywall (or 4-1/2 foot drywall in the case of 9 foot ceilings). The length of the wall really doesn't matter -- the drywall contractor will use 8, 10, or even 12 foot long panels as he sees fit. Small scraps have a way of being used above doorways or for casing window and passage openings.

A builder will quickly realize that your well-intentioned effort to optimize material usage will actually increase his labor cost; the net savings will be zero (or even negative). On the other hand, if your motivation is to optimize the materials as an eco-friendly  or resource/footprint minimization measure, then you may not mind spending extra on the labor to achieve that goal.

I'd suggest that you not even think about efficiency for the builders, but rather think about efficiency for the life of the building -- its lifetime operating cost. Consider whether you want to incorporate passive solar design ideas which can reduce your heating and cooling needs (and can reduce the up-front cost of the corresponding equipment, too). Consider the advantages (or lack thereof) of specifying upgraded doors or windows. Consider whether to require insulation under your concrete and whether to upgrade the materials and methods for insulating the walls and attic. Consider future-proofing by installing a thoughtful system of conduits at least for low-voltage electronics, and maybe even for your mains wiring.

In summary: builders are much better at optimizing than a homeowner or even an architect could hope to be. Let them look after that, and expend your own limited design time and effort on higher-level things.