Just picking your last question out of context to (re-)state what should be obvious:
Committees are bad, because you will never know what color the bikeshed should be.
You have exponentially many possible interactions between people in a group and any important information will almost surely get lost in the noise. Big committees are a wonderful stage for personal feuds, intrigues and outright sabotage (already in the formation phase).
The results you'll get will mostly be based on lobbying, popularity and whoever barked the loudest, not on benefit, cost, feasibility, let alone constitutionality.
OTOH, I don't really know what would be better. Smaller "committees", more like expert groups, can give better results if the right people are selected. Which is unlikely, given the present state of governments. At the moment it seems as if the best strategy is oversizing and over-bureaucratizing to slow down the process and limit the amount of damage done in that way. Meh. :-/