I think you can underestimate the value that zoo can (or could) add to the park.
I can't stand queuing for ever, it is just wasted time. And yet it seems, and I am aware my perceptions are just my own, that the building of queues is actually part of the business plan. Save money on having fewer staff, circle ride operations, build queues, sell fast pass.
The zoo can absorb hundreds or thousands of guests at any one time. I don't visit on quiet days, but when the park is busy...yeah, I'm round the zoo.
Areas such as the reptile house, which have had significant investment too provide respite on wet days.
Yes, there is a need to sort out some of the areas and ensuring that the right environments are there. But similarly the individual welfare and cases related to the animals aren't known to us. DMR may be the best place for them. The tranfer or alternate environments, no matter how they look to us, may not be suitable to them.