Honestly the biggest problem is the RPG genre itself, what consittutes a rpg?
If it's player control of a character, then every game is a rpg, including sonic and mario, if it's story again 90% of games have a story.
Hence why the rpg is basically a constitution of multiple different aspects that make up a whole, hence why strict criteria is required for something to classify as a jrpg, which stands for japanese rpg, there are a couple i came real close to disqualifying as well, soulsborne and monster hunter, monster hunter has alot of factors that honestly make it not fit the genre, but it's just close enough that i couldn't disqualify it, this is one of the reasons it's at C tier, in soulsborne's case i only played elden ring so i put it in not played because it really doesn't fit as a jrpg in itself as it's more similar to WRPG's, but i also didn't play enough of the series to qualify or disqualify it.
Leveling in itself is not required for the rpg genre, just some kind of growth progression, final fantasy 8, 10 and 13 for example didn't really have leveling systems but had a growth progression, in 8's case leveling actually hurt you, now that i think about it i don't believe nier or drakengard have leveling in the normal sense either, this is one of the reasons zelda is so hard to classify and everyone has their opinion on it.
Also my tier list was more about quality of the series, not nessisarily of my opinion on the games, my most hated game of all time is unlimited saga yet i still gave the series a A, wheras i'm personally fond of the lufia series and definitely loved parasite eve 1, but both of those series are C ranked due to factors involving the series, trash to a extent also has that as i really don't dislike agarest, but there are problems in the trash tier that i could not get them a C rank for.