I'm not sure I follow. I see the constraint of the first system as the natural fear of failure that comes from doing something new. It is an implicit constraint. The second system is less constrained in my view than the first.

The author of the essay linked seemed to be asserting that freedom from constraints will produce more wonderful solutions.

My interpretation of Brooks' observation on second systems is that they're what happens when the first system has been enough of a success to give people a relatively free hand to solve problems with it - so they try to solve all the things and wind up with an over-ambitious and unusable system, from which a pared-back third system emerges.