2K12 basically just combined the 80's cartoon and 2K3 together into one show, for better or worse (depending on who you ask). I wouldn't say it was an unfunny show, though it never got as goofy or comedic as 2K12 until the later seasons.
Although I'm not sure if I'd say Shredder was less intimidating (there's a reason his catchphrase was "none of you will leave here alive" was so iconic). Also just his character design was great, though that was also my first introduction to the Shredder so I'm probably biased .