Why don't you go and watch it for yourself. It's quite a joyful, warm and brilliantly made movie! It's just basically a fun experience. the RT ratings of 98% is understandable!
I also thought the preview looked horrible, and was surprised by the glowing reviews, but sw went to see it since both of my boys like Paddinton. The actual movie is split between really bad scenes like the one in the trialer and more clever and funny moments that deserve the kind of reviews the film is getting. Overall, as an adult, I thought it was just OK, but the kids liked it.
The bathroom scene in the trailer fits perfectly when you watch the movie. It's not a good way to sell the movie since the movie is a lot more than slapstick comedy but when watching the full movie, I loved that bathroom scene.