I've been considering working with (hiring) some developers at some point and creating a GUI that combines all of the best elements for engine testers enthusiasts and chess learners.
My question to you guys is:
What features would be absolutely essential in the PERFECT chess GUI?
Personally, I'll be aiming for the following:
- Winboard and UCI compatibility
- Attractive design, board and piece set/s ( and including attractive multi-PV analysis display - unlike Arena)
- Round Robin, Gauntlet and Swiss Tournaments
- Custom Opening Books (hopefully with ability to import/convert other books)
- Ability to clearly display UCI options for engines with a LOT of options (Rodent, Texel, Pro Deo, Gambit Fruit etc)
- TB usage/adjudication
- Openings study features
- Open EPD and PGN files
- Game user-adjudications
- Attractive Engine logo and rating display during matches
- Rodent and Pro Deo built-in (assuming permission from Pawel and Ed

- Beautiful engine tournament crosstables and engine rating changes on-the-fly (like Arena, but with beautiful visuals)
Anything else?