Re: user created puzzles!
In line with the Bram's comments I would suggest:
1. To award the same points either to the designer and to the solvers.
2. To open this puzzle to everybody (subscribers and non-subscribers).
3. To stablish some limits in the main page:
A maximun of 30 days (from there no points would be awarded, though the puzzle could stay only as a sample until a new one comes). In fact, it's interesting having always a link to this special puzzle.
A minimum of 7 days (to prevent the situation commented by bram that someone designs a very very difficult puzzle so that "only the creator" could solve it, since 7 days looks reasonabe to solve it).
In this way, the solver is motivated to solve it in those 7-days or very near to this inferior limit because if a new puzzle appears (and you do not know when) you lose the possibility of scoring those points.
4. To publish the puzzles according to a First In First Out list (the 7-day minimum time could be revised, if advisable, when the frequency of user-defined puzzes is higher than 52 per year).
And for a not far future:
5. To open the actual range (4x4 thru 9x9) up to 16x16, I am thinking now in the Christmas Puzzles, New Year, or those sent by nicow (Red Cross, etc.).
6. To improve
the software to include: negative numbers, operators like AND, XOR, and skipped numbers puzzles (i.e., a 5x5 with -9, -2, 0, 1, 5).
Any new feature is always welcome and challenging, I have observed the incredible success of the new 8x8 timed (even with only 1 attempt), it has shocked me having seen some players fighting around 2 hours to gain 1 point and to complete it (they have probably erased the full grid many times
).