It is such a leap forward we only have some vague ideas what to expect... We can reasonably expect it to revolutionize our understanding of the universe, its history and its future.

And as incredible as that is, there are even more dramatic advances coming soon that won't require quite the massive investment JWST did.

The 6.5 meter diameter JWST will achieve a resolution of 0.1 arcseconds (~0.5 microrad), there are missions in planning now that will allow ground telescopes like the 30m telescopes under construction now to operate at essentially their diffraction limit at even shorter visible wavelengths- achieving resolutions over an order of magnitude better, and some advanced Radio telescope missions in planning now are talking about micro-arcsec resolutions!

We are about to see a new revolution in astronomy.