So you want to increase to reduce later?
Very clever indeed.
Yes, reduce if necessary.
What's the problem with this?
If technology and adoption won't grow at rates projected, and if all that slack would cause some issues, it would be easy to adjust the future limits downward.
But there's no projection. It simply keeps doubling and the network don't grow at that rate.
Unless everybody will have Google Fiber 24/7 in a few years and there a mass adption like a big bank acceptin Bitcoin and promoting it, and that will not happen.