So I'm not an expert on the Canadian car market, but assuming it is similar to the US car market I would avoid another sentra. Newer Nissan vehicles have been getting much worse ratings, and they just aren't keeping up with other vehicles in terms of features and refinement.
If you would still like a car similar in size to the Sentra, I would recommend a Chevrolet Cruze. It has a small footprint (similar to what you are used to), better than average reliability, and much more comfortable.
I would also recommend the Honda Civic. Between the model years 2013 and 2015 they were slightly refreshed, and offer quite an impressive package. Their reliability is well above average, and maintenance costs are low as well. It is not uncommon to see Honda Civics with north of 200,000 miles on them.