Speaking as a Catholic, albeit lapsed (& some would say I'm "not a proper Catholic"), I have always had reservations about canonised saints. To be a Saint a person has to perform miracles after death and it seems dodgy to me because not one of us is perfect: at the same time, the Church exhorts us not to try and contact the dead so there are double standards. Suffice, I believe, to remember or read the memories of others, about people who did outstanding work. Apart from anything else, the canonisation process is lengthy and expensive. Surely time and money would be better spent elsewhere. However the traditionalists like it and it doesn't affect me - nor does it affect anyone else who isn't interested.
Mother Teresa is a controversial figure. I have read a great deal about her and have known some who went to India to help in her centre, or one of her centres, years ago. It seems to me that she started off well, with a good vision, but like many people, as her renown grew she felt she could walk on water. The mighty tumble. She can be remembered as a human being who certainly had a vocation to do good. It went wrong in some ways. Lesson to be learned - don't let anyone stay at the top for too long and do not put people on a pedestal.