Fun fact: due to they way intervening if-clauses work in the rules this basically says "this ability won't trigger unless it already has triggered thrice this turn", so it will never happen.

Also even if fixed about everything on this card cospires against making it a common: losing abilities, mana abilities, the weird condition.

I'd just go with something simple like "Whenever a player casts a spell other than the first spell cast this turn, tap enchanted creature." Much less words, same flavor. If you really care about the abilities, maybe a less headache-y "Abilities of enchanted creature can't be activated its controller's next turn."