Cool topic!
But I'd probably go with a very short carpet, the kind you'll see in kitchens. It would be warmer and more comfortable on your feet than tile or concrete, but still fairly easy to pick up bricks
I agree with this - it's the same thing I have for my LEGO room back home. Think "office" or "hotel" carpeting.
If you drop a brick on wood or laminate, that baby is gonna travel - small cylinders or cones could roll under (insert anything here) and you'll be running after them.

Plus... not comfortable at all if you have any thoughts of ever building on the floor.
A carpet that is short is better.
A - When bricks fall, they still make a noise, but they don't travel far
B - It's more comfortable for you
---> when you are standing
---> You can build or arrange MOCs on the floor without getting a sore butt, knees, elbows, etc
C - It's easy to have the "carpet-installer-people" cover the whole room.
---> The idea of the big squares of foam rubber that fit together is excellent (that's my Yoga Room!) but you won't be able to cover all areas of the floor as easily without cutting them and fitting them yourself
A carpet like this is good stuff
