Filling the Gaps: following in the footsteps of the Wildwood and the Angle

[MiniExpBounder]

I don't get why people panic what we don't have enough size on world map.

There is no panic involved.
Being committed to World-Building analysis, I voice my curiosity about the future of the development providing facts that may fuel a constructive discussion.

In last 5 years, SSG already replace region maps like Gondor, Rohan, Eriador.

Knowing what I know, I can not make sense of your statement about the last five years of development. Their process was just standard procedure, building the playable areas in free-usable lands.

Gondor region map don't have place for Umbar? Ok, how about Mordor region map? They need change it anyway when we reach Rhun, Nurn or other parts of Mordor

If R3 Region has no space for Umbar, since the R4 "Mordor" Region was made by duplicating the former, the spacing problem is the same. Note that such a "spacing problem" comprehend a physical and programming limit.
The solution would be of course to move all of the landscape in a North (plus West if they want some space for Nurn) direction.

Aside from having to deal with the change of coordinates, which would touch all of the geographical references in place for Quests, Spawn Points, Instanced Sessions, Teleports [...], they would also have to move all of the Mordor Instances in the Out of Bounds (if moving North) and both the versions of Mordor labelled as "End of all Things" and "Besieged" if moving West (wanting to retain some space for Anfalas in R4).

I stand very keen to witness the Road that the SSG team will take.

If you want to spend some time reasoning for yourself on such technical matters, just type "LotRO Heightmaps" in Google Pictures, and try to make sense of it.