It actually looks quite clean. Certainly a lot better than some of our legal databases. I guess the only suggestion I'd have is that it seems like you can have an account with the website but there's login or register button on the front page (or maybe I'm just not seeing it?).
One other point, and this is not specific to CanLII (I haven't checked whether this is the case) but I've seen that a lot of legislation databases have poor SEO. In fact, AustLII is usually ranked higher than governments' own websites when searching for laws. I think it's something important to get right because a lot of people just use Google/Bing/Kagi to search websites nowadays rather than using internal search engines.