Is what a different strategy/concept? Are you asking if irimi = preemptive attack?
There is no "attack" (or "defense") in aikido.
Just like there is no "opponent" in aikido. If there is no "opponent", wherefore the need for attack (preemptive or otherwise), or defense???
BTW, irimi is like reaching out to embrace an old friend.
So, I guess the answer is no, it's not the same thing.