There are many developments on the way...
This is a very abridged version of a post I am working on....
Laser guide stars

Laser guide stars have increased the amount of sky we can use adaptive optics on by about a factor of 100- right now AO is available to ~1% of the sky without lasers- with lasers that grows to 80-90%.

The astronomers are CLAMORING for laser time...

Interferometry

This is an infant field, its potential is BARELY starting to be realized, but its theoretical potential is immense. Optical interferometry has amazing potential- what we have done with current technology is impressive, what is possible in the near future is truly amazing...

EXTREME adaptive optics

Right now adaptive optics (AO) are limited to longer wavelengths- the simple reason is that to do AO you need to warp mirrors on a scale measured in fractions of the wavelength you are trying to observe- this is easier to do with long (near IR ) wavelengths than it is with the visible- But much work is being done to extend this to shorter wavelengths.

Short wavelength AO is being worked on NOW... There is a lot of money and effort going into the project- it will happen, the only question is when.

when it is developed then scopes like the Hubble will be truly osolete.

Telescope structural technology

Telescopes using one large single piece primary mirror are limited in their size- the largest is slightly over 8 meters, Keck demonstrated that a segmented mirror could do the job with many small mirrors used together. A 30 meter or 100 meter telescope will HAVE to extend this segmented mirror technology.

Hopefully I will post MUCH more later- I am out of time right now