Description
Pearl does not generate large grids well, unless the "allow unsoluble" option is selected, however I believe that there is a way which expands on this generation option that makes the puzzle still have only one solution, while allowing for a bigger grid.
The current "allow unsoluble" generation explicitly states that all possible hints are marked, which gives the player a lot of information that could be used by an autosolver to more effectively check if the puzzle is uniquely solvable (with the additional knowledge that all possible hints are marked).
This could allow for more puzzle variety and would be a more consistent design option (meaning puzzles have one unique solution), while seemingly not being difficult to implement. It should also be easy to mark the new kind of failures at squares where a hint is not placed, but the player made a path that requires one.
Some additional context for possible deduction rules and why I believe this is limiting enough to allow for bigger uniquely solvable grids:
-the first ever random unsoluble puzzle on a 20x20 grid I attempted required only one guess ever to solve, unclear if it even had a separate solution
-a black dot may only have connections towards adjacent white dots (again, considering all clues must be shown)
-a straight line of at least length 2 can only turn at white dots
-any turn of a straight line (of at least length 2) mustn't immediately form another straight line if there is not a black dot at the turn point