The Russians themselves replaced their Su-33s with the Mig 29Ks so I don’t see what deal is :)
I realize the J15 and Mig29K are different classes, but considering they are both carrier craft, it would be interesting to compare them.
Well, Su-33 is a naval version of Su-27 which is a rough equivalent for F-15, Mig-29k is a carrier version of a Fulcrum which is in a class of F-16.
J15 is a reverse engeneered version (at least it’s airframe) of T10 - a Su-33 propotype Chicoms bought from Ukraine along with the carrier.
Russians replaced Su-33 with Migs in order to keep Mig company afloat in the first place. It also make sense to have a smaller aircraft for carrier operations. Su-33 on a carrier looks just like a cow on a small inflatable.