I don't think a demo and rebuild of Terminal 2E is part of the current plan. I believe T2E will be remodeled, but not torn down.
As has been posted up-thread, the current project awaiting approval of the EIS and due to start construction in late 2021 is for the replacement of T1 and accompanying work on the field, both airside and landside. It is due to be completed in fall 2026.
The next major project to be undertaken by the airport should include the demolition of T2E, with construction of replacement gates connecting T1 and T2W. That will be an entirely separate project requiring its own funding, approvals, EIS submission, design and construction. It will obviously be many years away.
To the best of my knowledge, there is no major remodeling of T2E on the books. Maybe it's up to AS and AA if they want to add some windows, widen the concourse or add more concessions. I would love for AS to add a Board Room somewhere in T2E. I've heard nothing about such actions or even if it would be possible...
The problem with T2E isn't just crowding, it is the poorly designed gates placed incredibly close together, preventing simultaneous usage. Gates 29 and 31 can only be used sequentially, not simultaneously, and the same is true for 28/30/32. And the seating area? Not enough for one gate at each of these positions, much less two or three!
Expansion possibilities? Zero. Tarmac space is maxed out, and in fact, leaving T2E as-is would restrict future expansion of the planned T1. Amenities? No room to expand. Additional seating for gates 20-27? Can't happen. Any kind of "upgrades" to bring T2E upo to the level of T2W and the new T1 (when completed) will simply be polishing a turd. Its time has come and gone, but it needs to eventually go away.
Just in case anyone out there hasn't ever seen or dealt with the ridiculous layout of T2E, here's a map. Picture 450+ people waiting around in gates 28/30/32 trying to claim one of the barely 100 seats.
By the way, if you haven't done a Google Image Search recently for SAN airport terminal map, it's good for a laugh - not a single image came up with a completed Terminal 2 West. Not one. Granted, I could have gone to san.org and gotten the map there, but I want to publicly "shame" ifly.com, as their map of SAN is more than six years
out of date. How embarrassing for them!