Do you say that about 3 because you don't think it can lead to great abuse to provide room and board to soldiers during peacetime? That's why our Founders put it there and it has been effective in protecting homes from that intrusion for over two centuries.
Countries without a Second Amendment might become convinced that they need to sometimes quarter soldiers in private homes. Those who are armed fear the absence of a strong central military much less. They are prepared to organize themselves in Militias and to protect their communities without government help.
I say #3 because the exercise is to remove two of the first 10. This isn’t an easy task, but we have to choose. My thinking is that of those 10, there has never been a case on #3, and as far as I know, it’s never happened since the government has been adopted. So if we have to remove some, #3 seems like a pretty good candidate to me.
#7 is my second choice because, again, we are dealing with the lesser of evils here. I tend to think jury trials in civil cases are overrated, and the elimination of them might actually help to lessen some of the large verdicts that we’ve seen in the past few decades. OTOH, it gives even more power to life-tenure federal judges, but that risk seems to me like the least bad risk compared to removing some of the other amendments.
Also, for purposes of this exercise, I’ve interpreted the assignment to remove an entire amendment—not just a clause.