The Finance Ministry under LGE is responsible for the bastardization of the MRT2 scope when Pakatan was still in power. No surprise that public transit is at the bottom of their priority list.
Looking at that plan, I believe it may have been omitted because you'll have to build right under this project, a few shoplots and a private empty land across the road, which will surely involve multiple parties. And based on past experience on how certain neighbourhoods oppose even something as minor as public transit stations exits and placements, I wouldn't be surprised if this may be the reason why MRT Corp would rather not raise the ire of those parties.

Sure one can argue that New York's subway tunnels do go underneath buildings without issues, but you know how fussy or protective most Malaysians are when it involves their backyard.