An option to be able to increase capacity is highly unlikely due to the stadium being fitted across North to South (narrow part of the land area)
this is due mainly to the tv companies preferring pitches this way (sun issues etc)
LOL
I would imagine its mainly due to the grass.
But anyway, I dont have a clue why the Stadium is being planned the way it is, but im fairly sure its not cos of the TV companies.
According to Meis at the recent Q&As, broadcast is one of the considerations in the North-South orientation convention. He also mentioned how it reduced the setting sun hindering goalkeepers.
From UEFA's guide:
Orientation
When planning the orientation of the pitch, the primary
consideration is its position in relation to the sun and
prevailing wind. In Europe, a north-south orientation is
generally considered best, as it means that, in the evening,
the setting sun will not hinder the vision of one team more
than the other.
Assuming a north-south orientation, the main TV camera
positions should be in the west stand (main stand) to avoid
problems caused by the glare of the sun.
It is particularly important that any deviation from a north-
south direction is kept to a minimum if the stadium and
pitch are not covered. In such cases, the general rule is
that this deviation should be no more than 15° from the
north-south axis.
In certain cases, site constraints may dictate an east-west
orientation, although in general this is not recommended.
In such cases, special efforts are required to minimise the
contrast caused by some areas of the pitch being in sun
and others shade, and thereby minimise the impact for the
TV cameras.
http://hns-cff.hr/files/documents/9406/UEFA Guide to Quality Stadiums.pdf
From FIFA's guide:
Playing field orientation
Great care must be taken regarding the angle of the playing field in relation to the sun
and the prevailing weather conditions. Match participants, spectators and media
representatives must be protected as much as possible from the glare of the sun.
However, the effect of a stadium’s roof on the playing field must also be considered.
When there is a natural grass pitch, it is critical that there is enough light and air
movement to sustain the healthy growth of grass. All sides of the playing field must
receive a reasonable amount of direct sunlight.
A north-south field orientation is often considered ideal but more sophisticated analysis
has led stadium designers to choose an angle equal to the average direction of the sun
at half time in an afternoon game.
https://www.ksi.is/media/mannvirki/FIFA_Football_Stadiums.pdf