I believe the current capacity is 6,500 seats, not sure if & how many people are allowed to stand in addition (only for T20 I think), the 'new' Ground was going to be 8,500 so an additional 2,000 seats are to be added presumably mainly in the new Pavilion & surrounding area. A great pity we seem committed to spending a few million for a modest increase & this will take a considerable time for Essex to recover the costs in Match receipts etc, it will also lead to increased traffic on match days in an already congested area (rush hour driving into Chelmsford now is very slow especially on Fridays for T20 night matches.
An increase in capacity in any sporting arena, has to meet strict criteria both in terms of licensing authorities, as well as the ability of the surrounding transport/road infrastructure to cope with the resultant increase in footfall.
So, for example, I'm sure ECCC would have rather liked an increase to 10,000. The problem is the aforementioned infrastructure would reach gridlock quickly and consistenly. Circulation space is a key consideration too. I would suggest that a 6k attendance at the ECG feels uncomfortably constricted, with inadequate toilet and catering, not to mention shelter from bad weather. The more people you throw into the mix, on basically the same footprint would only exacerbate such issues.
Now, add in a high density series of apartment blocks - 350 I understand? Each dwelling occupier has an average of 1.25 cars = (437 vehicles). I've personally seen no explanation, apart from the vague promise of a multi-storey car park, of where exactly these cars are going to go? Add into the transport issues, of how the narrow New Writtle Street will cope with cricket attendees, as well as allowing apartment occupiers, free and unrestricted access/egress to their homes? Do you think they may be a little upset if they are late for their trip to the supermarket because they are unable to leave site
Stop and consider that the ECG is served by this sole vehicle access route - then stop and think how any of the emergency services will have the capability to respond to any emergency during a Friday night at the ground.