No, I don't think so. People like him for very good reasons:
1 - For one, he's been the main in the most beloved games of the series (RE2, RE4 and yeah, there is RE6, but most people will say to you that his campaign was good, thanks to it's atmosphere) - People associates his face with those game, and that makes them like him instantly (his character reminds them of the good time they've had with those games).
2 - A lot of people that played RE4 (or even RE2) aren't fans of the series (they played those because they've heard good things about them, and noticed their popularity - most loved them, but didn't come back for more), what come after wasn't praised at all (or in the case of Rev2 wasn't given much space, unfortunately), which is why most of the casual fans didn't come back (those who did, didn't like RE5 much, with some exceptions, which ended their relationship with the series). Given this context, it makes sense for them to like Mr. Kennedy, since that's the character they used the most (or again, the one they associates the most with good memories of the franchise).
3 - RE4!Leon it's the best Leon of the series hands down (and RE2!Leon is also a quite nice character), he's funny, he's sassy and he has some of the best quotes of the franchise - and as I said, most people associates his face with that game.
4 - Yeah, he's the main of the CGI movies, but I don't think that that makes him overrated; for one, it makes sense for them to only choose one lead (they want continuity between the movies, mostly for the people that didn't play the games, and it makes it easier to do so with just one lead, and-->) besides, every movie has other important RE!Characters in them, we follow Leon's story there BUT much space is also given to Claire, Ada, and more recently to Chris and Rebecca - they also weren't in there just for fanservice purposes (unlike the action-movies), they had a role (I'd say that Claire and Chris shared the spot as leads with Leon - I'd also argue that Chris was even more so than Leon, and that Leon was there just to provide a connection for the ones that didn't play the games), and they each had various scenes dedicated to them (most of which were quite iconic tbh), they weren't put on the sidelines to make Leon look good, they were all equally good. There is also the fact that Leon was the character that was ****ed the most by Anderson's movie, so fair is fair (lol).
Btw, I'm not saying that what come after RE4 is bad, not at all (I love Rev1 and Rev2, they are some of my favs RE game - I enjoy RE6, and while I don't love RE5, I do love it's DLCs), I'm just talking about some patterns I've noticed (I know a lot of people that played and loved RE4, and even RE2, but most of them stopped after being burned out by RE5, most of them will also tell you to go and play those game if you haven't).
Now let's take a look at the main saga:
Resident Evil 0: Rebecca Chambers & Billy Coen
Resident Evil 1: Chris Redfield & Jill Valentine
Resident Evil 2: Leon S. Kennedy & Claire Redfield
Resident Evil 3: Jill Valentine
Resident Evil Code Veronica: Claire Redfield & Chris Redfield
Resident Evil 4: Leon S. Kennedy + Ada Wong
Resident Evil Revelations: Jill Valentine & Chris Redfield
Resident Evil 5: Chris Redfield
Resident Evil Revelations 2: Claire Redfield + Moira Burton & Barry Burton + Natalia Korda
Resident Evil 6: Leon S. Kennedy, Chris Redfield, Ada Wong, Jake Muller & Sherry Birkin
Resident Evil 7: Ethan Winters
Now, let's count!
Leon Scott Kennedy: is the lead in 3 games
Jill Valentine: is the lead in 3 games (+ 2 DLC in RE5)
Claire Redfield: is the lead in 3 games
Chris Redfield: is the lead in 5 games (+ 1 DLC in RE7)
^ I think that this speak for itself.
Also, the fact that you don't like RE4 doesn't mean that it is overrated, that game wasn't just a great game, it was revolutionary for it's time - which is why people loves it so much.