Interesting perspective. I've been asked about HL several times by "ultra casuals" and I always told them that it's a 7/10 if you're not a HP fan, and a 9/10 if you are.
That 45 minute overview State of Play or whatever it was when they showed all this stuff you could do in the game plus the world, combat, etc. won me over and got me hyped into the game. Watched the combat and loved the setup to it where you have all these different types of magic and all on a cool down which I prefer over anything because you can then keep using it and changing to other tile sets of how I had my magic setup, oh man, it was so much fun and enjoyable. I played the game 100% on hard and it was just so damn good. I never watched any of the movies or read any of the books. Never cared about the IP itself. Star Wars and Marvel/DC is very similar where I won't watch the movies or read the books but I will play most of the games. lol
My personal ratings were -
Visuals - 9.0/10 (some facial animations and character models left a little to be desired but im not a graphics guy as it's the third most important category to me and the world itself, design, art style, etc. was so immersive that I think I spent over 20 hours in the castle alone just looking for every book and item to collect and find every secret)
Audio - 9.0/10 (loved the music for the most part, sound effects were really good and voice acting was solid)
Combat/Gameplay - 9.0/10 (while I had some issues with the camera and targeting certain enemies at times, the magic combat was great and felt very fluid and responsive. Had a blast with it. Only other negative was stealth was crap and AI at times could be bad but all in all, much better than I was expecting going in)
Story/Characters - 7.0/10 (this is probably the category where Harry Potter fans would like more, maybe? I don't know but I thought the story and characters were really good. Kept me entertained to the end and I really enjoyed it overall but was the weakest aspect of the game for me)
Overall - 8.5/10 (great game and is my 5th best game of 2023, 4th if I exclude Dead Space remake. Was hoping for a meaty expansion but going straight to a sequel works for me too so I don't have any complaints)
I also completed almost everything 100%. Total is around 95% or something like that. I would have to check but simply enjoyed the game overall and as long as the sequel is equal to this game or obviously better, im day one for it.