Do you really need to run 3 MST? Part 1

I want to explore a concept that I have been messing around with.  In the last few years, there have been many decks that have chosen to forgo Spell based Spell/Trap removal, namely Mystical Space Typhoon.  Consider this:  The decks that you actually want spell and trap removal against, run in excess of 10 traps and they happen to set multples on their first turn.  In your opening hand staring down a Fire Fist Bear with 4 set cards, how many of those 6 cards do you actually want to be Mystical Space Typhoon?