Nobody is more in favor of getting rid of Shrek than me... but replacing it with another 4D-type show seems like it would be a really poor decision. I get that it would be relatively easy and cost-effective, but I think I'd honestly rather just see the building leveled and incorporated into a new entry plaza before another 3D experience. Of course, my ultimate preference would be for a multi-level dark ride to go into that spot.
I think the series is fondly regarded by its target audience and is successful enough, although the domestic box office trajectory is decidedly down film-to-film. Five or six years ago would have been a great time to really use the IP; I'm not sure how much life it still has left in it.