Myself and many of my friends got our applications approved very quickly WITHOUT a Study Plan.
Opposite to popular believes, not having a Study Plan is not a valid reason for rejection. And not everyone has to explain why they want to study in Canada, why they choose the course, etc.
For reference, I am from Vietnam and I was a high school graduate applying for a Bachelor degree at Carleton University.
I did NOT submit a Study Plan. I followed the required documents section in my online application strictly, and nowhere did it include Study Plan. So I didn't submit one.
After that, I was worried because many people on this forum said that I will be refused without it. But then, I got approved in only 16 days with no issues.
All be it, I was applying under SDS and I have a strong academic record, strong travel history, and the progession from high school to bachelor degree at university is a perfectly reasonable one and did not need any explaining.