At the end of RE2R, Leon was holding hands with Sherry and Claire with a grin on his face happy they made it. So even by remake standards, it makes no sense to make Leon so serious in RE4R. All it did was make him unlikable. Calling RE4R Leon better is straight up delusional
Hot take:
RE4RE Leon is a better character than RE4 Classic Leon.
Lots of RE fans lamented Leon being moodier and more serious in Remake, and I get it. Believe me, I do. His constant wisecracks and devil-may-care attitude made RE4 Classic a truly fun experience. However, this really does not fit the established Leon.
Think about it: In RE2, he was a boyscout rookie cop. Then in 4, he's a completely different character. He's basically Dante from DMC, with the events of 2 barely being mentioned.
In Remake, however, his sass is recontextualized. He still drops quips and one-liners, but this time, it feels more like a coping mechanism to the awful situation he is in. And the trauma of RE2 is more clearly felt, both in a lengthier intro sequence, as well as him clearly having survivor's guilt from failing to save anyone in Racoon City (except arguably for Claire, but she did pretty well on her own).
It may be because I became a Resident Evil fan quite late, specifically with RE2 Remake, but I feel that this change fits Leon's continuity far better. And again, I understand the sentiment of missing the old devil-may-care Leon, but from a narrative and characterization standpoint, Remake Leon runs circles around his older counterpart.
Thanks for coming to my TED Talk.