>>38441106The biggest difference is that Detective Pikachu is set in a world that Pokemon are very much a part of whilst Sonic is essentially an alien on Earth.
Even if Sonic looked like
>>38441029 on the right, the movie they've chosen to make means sonic is always going to look weird by comparison to all the non-CG, non-anthro inhabitants of the human world.
Detective Pikachu, however,will feature a ton of other CGI pokemon as both main characters and parts of the background as well as CGI signage etc thats all designed to integrate pokemon into the world itself. I think, regardless of how much you hate the CGI in both of them, in the end, Detective Pikachu would be a much more enjoyable watch because you aren't just watching a single, obviously CGI character in an otherwise real world setting. The parts that are CG won't be so glaringly obvious in every scene because its also present in the architecture or the background chars etc like in the marvel films.