I don't think your argument is a valid one because our population has increased x 10 since the constitution was ratified and although we have our problems, I don't think we can say it is because of our population growth. doubling or trebbling the population won't cause any harm, in fact it would strengthen our power and influence in the world, much less make the lives of those who come here infinitly better.
In fact, if the thieving federal government would give back all the land it has stolen from the states out west, we'd have plenty of space.
We have less representation than before.
This is significant, and if the population were 1 billion, how many people is that per senator? Isn't something like 1 senator per 10,000,000,000,000,000 people? How do you get adequate representation with those numbers?