This is the simplest and most accurate discription that i can offer
water has a high specific heat capacity meaning it takes alot of energy to to raise the temp of water by 1 degree celcius.
water has to circulate around the cylinder block and head to absorbe the heat from the engine. if you remove the thermostat the water would just flow past and not get eneough time to accmulate the heat from the block to release it in the radiator.
you can have a situation where the engine is running hot and the guage (which checks water temp) shows normal.
All that being said leave ur thermostat in. if you are afraid of it failing closed and over heating, change it every 160 000 km or 100 000 miles and replace it with one that fails in the open position.
an example can be found here
http://www.motoradusa.com