Kendrick did sound like Wayne on C4 but that was the concept of C4 mixtape. When he was on a couple of songs on Game's BWS & YKWII vol.4 mixtapes and Jay Rock's mixtapes (& on their collab mixtape also) he didn't really sound that much like Wayne, (sure their voices were still somewhat similar)
It is true that Ab-Soul & Jay Rock were a bit more polished than Dot & Q back then. Q wasn't as aggressive and Dot wasn't as introspective/complex but they all were still spitting
To me Drake sounded more like Budden & maybe Phone early on, but with less depth and worse wordplay.
KDot & Jay Rock had a mixtape where they only rapped over classic New York beats. Outside of Jay Rock's first mixtapes and Game's mixtapes I'm pretty sure that was the first KDot project I heard & after that I went back and checked out Training Day. On the NYC mixtape KDot did basically Hov&Big imitations, check out Kick in the Door freestyle for example, he's basically mimicking Biggies flow and voice. Interestingly enough they also rapped over Shook Ones pt.2 on the mixtape, but obviously most rappers remember their BET cypher over that beat
Also to be fair, around 2009-2010, after Q and Ab-Soul had dropped their first (TDE) mixtapes KDot was the weakest member to me, I still felt he was talented, but I liked Gangsta & Soul and Longterm more than any KDot project.
OD and Section.80 really changed things a lot, but to me GKMC is where Kendrick proved that he's one of the best artists of his generation and not "just" a good artist/MC