Fencer, I understand your decision and I respect it. I hope that solution will placate as many people as possible. I will still try to urge players to learn to play the gamne the correct way, but if thye do not wish to, they still have the option of p[laying without the restriction, so they should have nothing to complain about.
I have a few thoughts though that I hope you will take into consideration--
1) I hope this option to turn off the opening restriction STAYS with the 13 X 13 board and does NOT get added to the 19 by 19 board. As it is, the 13 X 13 board is not an official pente board, so I am more able to accept the restriction being lifted as long as it stays on that board.
2) As far as the ratings go-- I think it is a problem for the ratings to have small pente players all rated together if some are using the restriction and some are not. Players who play without the restriction have no business being rated with those who DO use therestriction.
This may be too minor of a problem to deal with, but if I may, I would like to make a few suggestions for you to consider.
suggestion 1) Allow only unrated games if the restriction is turned off. Tihs is actyually how Dweebo used to have his site run at Dweebo's stone games-- players at his site oculd play unrated games and thus turn off the ratings, which keeps the ratings fair to those who DO use the restriction. It really is unfair to those who play with the restriction to be rated with those who do not use it.
Suggestion 2) Actually create a separate variant with a separate name-- then there will be one game called "small pente" that HAS the restriction, and a new variant could be created called "No restriction Pente" which does NOT have the restriction. This owuld give players clear choices about hwich game to play, and everyone would be rated fairly and on equal footing.