I wonder if that might be due to a long time gap since the last sandbox Mario game, and it was a refreshing experience after many subpar games (such as too many NSMB games in a small time frame, and 3D Land/3D World back to back). That's not to say Odyssey isn't a good game, because I very much like Odyssey, and prefer that style over Galaxy games imo, but that might give an explaination as to why Odyssey might be acclaimed.
i like odyssey
jokes aside ive done three full playthroughs, even basically 100%, but i cant yet form a very good opinion because all of those were before i played other 3d marios. now that i HAVE im curious to start another playthrough and see what id think of it now. atm though i cant be much critical of it aside from a very few moons stinking and the fact that the worldbuilding and npcs isnt all that spectacular compared to sunshine. i never even found 100% tedious like everyone says it is