That does not make any difference. I just wait until I can be the ID I need to be next in line.
Which ID do you want? How long do you wish to wait?
And I do this for every next SH, and as I have more next SH, I gain more ability to do this more often. My attack grows power until I am always next.
No, the rate of honest SHs is fixed and does not depend on how many SHs you possess currently.
Its output is known for all of future before I choose my ID as stated above. The only way for the output to not be known a priori, is to have some dynamic entropy. You can't escape the fundamental of the lack of ongoing entropy.
Sure it's known, and what? Suppose you know that you'll sign TB#35677 in the next day and TB#22789 in the day after that. What power does that give you compared to the case when you didn't know that? How to exploit that power?