No, the FAA is not proposing any stricter standards for S-LSA than they already do. S-LSA airplanes and gliders CAN tow, you are confusing the differences in proposed changes in E-LSA and Exhibition Racing certifications.
In summary, the proposed regulations do not change anything with S-LSA. We tow, we fly at night, we fly through Class B airspace, we fly through the DC SFRA, and we fly to 18,000' with our glider ratings in the Phoenix. Nothing in the proposed regs changes any of that.