Another Sonic show would be successful.

[Jammin']

I feel like another slice-of-life Sonic cartoon would actually be very popular.
I think the reason why the Sonic Boom TV show was as big as it was because it just showed day-to-day life for Sonic characters while being self-aware and funny.
I'd say it's quite reasonable to say that a similar concept but in normal Sonic canon (and maybe a little more serious) would be cool too.

 

[GingerSRB2]

Sadly, i'd doubt if Sega will make a new cartoon for this decade. Sonic Prime, as it currently stands, is a missed-potential flop, making Sonic be in a rough spot for most of the community. The show just...exists, when it could've been so much more than just an another way for Sega to cash in for the kids.