oh yeah there was this episode where even Penny said Leonard was the center of the group but I honestly appreciate more how the rest of the cast around complement rather than focus on Leonard. Howard and Raj are way more funny, the show did try to make Leonard the focus because he was the one dealing with Sheldon, over the last seasons they start setting a smooth ending , they all getting kids and married and distant Leonard from Sheldon but this was potentially intentional to grow other characters to intentionally release spin offs