You don't get banned for applying many times only real reason people get banned is for providing false information. These rejections are part of their record now & each must be mentioned as prior refusal during application.
Remember regular visa is maximum 6 months at a time, how will they justify reason for going to Canada on a regular visa? They will have to show that they are coming back and have strong ties to home country, difficult given spouse is in Canada. I suggest you go get your SP and then they can try SOWP again.