I would like the display of a game -in-progress to show the PREVIOUS MOVE as well as the most recent move? Why? Because in a “bot” game, the “bot” move is so quick that I cannot see where the human player moved. And I’d like to see that!
Maybe “o” for the current move and “-” for the previous move.
If you’re spectating on another player’s game, I believe you can enter “Analyze Mode” by simply pressing the “Left Arrow” button on the keyboard. This will let you see all the moves that have been played so far in order, and the move graph will also keep updating with the new moves in real time, as far as I know.
This option would also be useful in some correspondence games where seeing my last move would make it easier to remember the game and what I was thinking. It would highlight if my opponent has tenukied.
I disagree with the SHOULD of the title. This is at most a COULD (via opt-in preference) because I for one wouldn’t like that as too much visual clutter (it is standard across many go servers and go editors that only the last move is marked). And realistically OGS already has too many preferences, and lots more important things to spend development resource on, and the current solution of left arrow into analysis mode to see as many previous moves as you wish works well; so it’s a NO from me.