Are you talking about expanding Disneyland Park into DLF parking west of Disneyland Dr.?
If so, my answer to that is that DL doesn't need it. I think while anecdotal, the
trip report (so far) by
@PUSH is a perfect example. I don't want to put words in anyone's mouth, but they visited for four days and have reported on three days so far. They went to:
- DL Day 1
- DL Day 2 until the sun was going down, went to DCA including WOC, then back to DL afterward
- DCA Day 3 until this...
...so they went back to DL.
(Even if they went back to DCA Day 4...(we'll find out

)...the fact they had never been to DCA before and felt they had done it all in so little time is noteworthy.)
But the point is, this Disney Parks fan has spent so far a majority of their time at DL rather than DCA even though DL is similar to MK, which they've been to dozens of times.
DCA, which charges the same admission as DL, is desperately in need to more to do and more reason to hang around, to come close to balancing out crowds with DL. If they expand DL into DLF it will just throw the balance off more.
@PUSH also mentions the issue of walking to the farthest reaches of DL to get to attractions, and a DLF expansion west of Disneyland Dr. will only exacerbate that...imagine how far that is from TL. And it will ruin the symmetry and beauty of Walt's park layout (a complaint I've seen about Fantasy Springs at TDS).
Whereas DCA is already a lopsided, inelegant layout, or as
@PUSH said it:
The DCA DLF can't fix that, but it's not going to hurt as much as it could at DL. And if they were smart they would have embraced this long, right-curving lopsided design and celebrated that with a strong spinal path with transport (like the trolley or a Tokyo DisneySea style elevated train) to turn a fundamental bug into a unique feature -- and provide transport from BVS to Simba and back for tired feet.
So, DL doesn't need expanding over there, and it might hurt the overall park's feel. That land could be used for whatever hotels, waterpark, etc. they need at the Resort. DCA meanwhile desperately needs top tier themed areas and attractions and Simba happens to be the spot available.