That's only to a certain extent. You can imagine a set of all the pieces of art you can make and all the interesting pieces of art in that set. If they're are few interesting pieces, then the constraints do more harm than good. A good medium for expression will allow you to both express many ideas and restrict you from expressing the uninteresting ones.

To make this concrete, in programming, type checking eliminates all the programs which would have a type error so they are good constraints. But some languages constrain you in arbitrary way which hurts. For example, Java doesn't let you do any functional programming and has a weak type system, which means introduces design patterns.

Ian Bogost wrote a good piece on this called "Shit Crayons" comparing games like Spore to Photoshop, where even though Photoshop is more powerful, most of the stuff you can produce is bad, supporting the idea of constraints. But then he took apart Minecraft for being overly restrictive, causing many things like houses to be dull. http://bogost.com/writing/shit_crayons/