I understand where you are coming from on this - I used to think these were good ideas as well.
Over time I learned that nothing ever gets done anywhere without a trade, and the more people involved, the more trades need to get done. With 100 senators and 435 congressmen, that is a lot of trades. If I were in congress, do you really think I would trust the rest of congress to go along and vote for something "now" in hopes that they would vote for what we agreed to do in the "future". Not likely.
One could make a point that if there were only 125 or so vs 535, the problems would go down by the same amount - about 4x. I am long past the idea that reasonable citizens are listened to, so having a lot of representatives vs few is just an economic decision to me.
Adding to this complexity, is the short cycle time of the congressional election cycle. Every 2 years the reps need to raise enough special interest money to be re-elected. One could make an argument that if the election cycle were 6 years, the problems would be reduced by almost 3X.
Taken together, this would imply that having just one house of congress with 2 reps for "small" states, and 3 for "large" states, would reduce the problems by 12X. Not likely to happen though.
Personally, I would ban dual citizenship for anyone 18 or older. At 18, you are old enough to decide if you are "Really an American or not". That doesn't mean throw people out, as you could still provide people born as dual citizenship "resident alien / green card" status instead. It would reduce some strange behavior people have though.
Perhaps you can give some examples of what you are trying to solve with #2 though - lost me a bit on that one.