I wouldnt necessarily worry about people’s bad reviews, imo people are generally more likely to go and put up a review if they’ve had a bad time, than people are who had a good experience. So, what in reality is a minority of the people, seems like a large portion of people because they are the only ones writing reviews.
With that said, I’ve looked at pictures of that place and considered staying there before, and it looks nice. Its all in old victorian style, similar to the Royal York, which is a nice hotel. If its all in good shape, someone would need to be a dumbass to say it was dated. If its run down, then thats another story. However I dont know anyone who has stayed there so I cant offer an opinion.
The only problem with the Westin Harbour Castle is that you cant really walk anywhere from there (Yonge st, shopping, etc), but cabs are abundant and cheap.