Give prof subjects they can teach and then just create the activity without having to select the prof rather let the software do it to minimize conflicts.
If you have 3 profs for the same subject one could be assigned to a class automatically rather than having to shift it around manualy

Option to include alternate teachers as an option where more than one teacher is qualified to teach a class. This would further optimization and reduce timetable conflicts while avoiding manual substitutions.

Be able to preference the same start time for classes throughout the week as part of the optimization process. Eg 8:30 MWF or 2:30 MTWHF, etc. but let the program move the class as a group for optimization.

In NYC we have to be cautious of the UFT contract so it would be nice to be able to preference the solver to deal with certain errors before the other errors. The card conflicts and the the teacher gaps absolutely need to be dealt with before the same day subjects so we aren't in violation of the contract. The solver seems to do card conflicts and then same day subjects which is not helpful.

We need to be able to see the logs for any given timetable. We should be able to see the details of who created what, who modified it, when, etc. to avoid any confusion - especially when multiple people are working on a certain table. Could we start from here maybe? Because logging is a somewhat standard procedure, so hopefully it shouldn't be a problem to add that to the website. If such a feature is already available, I couldn't locate it. There is only the time of the last modification under the "Open Timetable" menu.

save 'view' settings: 3- classes, 67% zoom etc.

Currently in order to display the groups info in a card you need to add the class info. This results in cluttering the timetable when several classes have groups having a lesson at the same time. The intended behaviour however works fine when exporting as HTML Spreadsheet - it only displays the group and not all classes.
The same should happen when Printing the timetable direclty from the print option

It would be great to have an option to put constraints on how many times a class can show up for one teacher in one day so as not to have one class show up 3-4 times in one day.

A WordPress Plugin to pull the calendars from the Prime Timetable website into other WordPress website would be very helpful for distributing schedules on a portal.

If two groups are places together, have both groups listed in a single box.

Seeing an overall view of how you lessons are organised not just mulitple cards would help. From this view the curriculum could be rejigged.

When exporting completed timeable to a school management information system sometimes the class codes need to be already predetermined. Currently Prime auto generates the class code once timetable is completed. Adding a column to the import tab allows a school to maintain the class code it wants.

Lock down classrooms so its much harder to move them (eg by right click and edit)

... in our case we book rooms in distinct locations and we cant risk moving them around by accident.

Get Spanish language interface