Not to go against atemi, just not clear to me where the logic in this particular argument is going.
Timing, hes not going to be doing a 100 things at once.
Find the opening, take advantage of it, and work fast.
It really is a depends...if the first thing he does is runs up and knocks your block off...suppose your right, not much you will do. - It depends on a number of factors.
Suppose the best one would be to run...well, in truth not get started.
But if your bent on getting started not using atemi isnt going to help you much as he will be doing everything he can - heck, while we are at it, lets go all out old fashioned juijitsu and bite and gouge. - in a real situation, you do what you can.
In doing that, I suppose if you can, offset him and see if you can pin the big fellow...what do I know about such things though...definitely not the expert.
p.s. - very little 'logic' in my post as you may see... things are as they are.