My first love was the NES in the 80's. I got it in 1986... I was 7 years old. I even had a snes BEFORE I got a Genesis... but Sega's games and franchises are more diverse. Does Nintendo have a Shenmue? Do they have a Panzer Dragoon? Do they have a Night into Dreams? How about a Crazy Taxi? Jet Set Radio? No? Ok, how about Toejam and Earl then? Still no? 

Nintendo's IP, or core IP... most of it was created in 8-bits. By the time we got to 16, 64 and 128 bits, most of what they created was just evolutionary jumps based off of their NES genius. Zelda, Mario, Donkey Kong, Metroid...all started before or during the NES era. 

Well, you do list a good amount of good IPs Sega had in the past. I really enjoyed Toejam and Earl as a kid, and Crazy Taxi and Jet Set Radio were cool games as well.

Shenmue
Power Stone
Wiz & Liz
Toe Jam and Earl
Nba Jam
Mortal Kombat(real edition)
2K series
Skitchin
Streets of Rage
Crazy Taxi
Sonic 1&2
Contra 3
Ranger X
Moonwalker

Comix Zone

Pit Fighter

Eternal Champions

Damn I could keep going but I'll stop. Just games i really loved playing on the Genesis

Probably the Sonic series, I like the Genesis, CD, and SA Sonic games a lot. I also felt Space Harrier was cool. Not sure I have many more faves XD Do the Hatsune Miku Project Diva games count as Sega games? They do produce them after all, but idk XD

Haha, yeah, I guess they do. Not only because they produce them, but it felt like Miku was starting to replace Sonic as their mascot. u_u; She even does the "Seegaa" thing in the Diva games... I do like those games though, : P

Well she IS blue v.v maybe they could do a Sonic 06 remake and replace the princess with Miku XD actually... lets not give Sega any ideas... I like them a lot but Im abysmal at them

Panzer Dragoon, Nights into Dreams.

Yes its their IP