While I am tired of comedy sequels coming out decades too late, I am cautiously optimistic about Shrek.
Given its animated nature and fantasy setting, there isn't a lot of pressure to explain why the characters are all decades older. You can just set it right after the last one, which I think avoids a pitfall a lot of late sequels fall into.
Additionally, in my opinion, Shrek actually has a pretty strong track record. I mostly rewatch the first two, but the fourth and Puss in Boots 2 (if you count that as a Shrek movie) are both really good also. (I can't comment on the first Puss in Boots movie since I never saw it, and we don't need to discuss Shrek 3...)
I think it COULD also be fun to see Shrek lampoon more of modern Disney, since a lot has changed for them since the early 2000s; but it feels like Shrek has moved further and further from that style of comedy and have moved more into irreverently twisting broader fairy tales instead, so that doesn't feel very likely to happen, unfortunately.
Seeing as how the movie is years away, I think it is too soon to be making claims in either direction for the movie's quality; all I can decisively say is I really hope it doesn't disappoint.