Messi and Ronaldo is superstar, mean 8* player, a free tranfer player mean 2-3* it 's about 18th to 20th club. it's how it compare to reality.
if you chance you team everyday your team can't stand in forme.
random is a facteur but it is programmed so it mustn't be totally ramdom. there is always law in the random, in the case of top eleven the following maybe the way it works:
at x minutes. random ball for 1 club probability = no even (50% i thinks) then team A: team B ramdom respects the ball possesion
then random to the player has the ball: midfield (50%) ST(30%)(def 20%)
then ramdom : lost ball or shoot or pass or make a counter attacts , random facteur depends on quality, form
then random : goal or not, corner or not, freekick or not .....