I have been the same neighborhood for over 5 months now and asked about the next change would be happening.
Back in Nov I asked about it...and was told
The neighborhood merge system is under review by the developers. Neighborhood merges are handled automatically by the server. Support can do nothing to change anything about a neighborhood merge.
The new neighborhood merges, as announced back on 07-18-2013 over <
Click Here >, have as their primary target the players' technological advancement. Ranking points come in second, only to determine where "chunks of players" are cut off from the old neighborhoods (which are now merged into a new one).
The merges still take ranking into account, but very slightly as the primary focus is technological advancement. One could see from this that ranking points do not pose any significant advantage --- they're gained from collecting supplies & coin, battle points, and buildings in one's city. It basically only shows a player's activity level, and does not really reflect their 'game progression'.
The neighborhood merge system works by splitting neighborhoods into 'blocks'. These 'blocks' are determined by the largest gaps between players in terms of their research tree progress. It is therefore possible for players to end up in 'blocks' whereby, once placed in the new neighborhood, create large gaps between some players within that new neighborhood.
Hopefully this explains how this can occur, and future merges will help to level the playing field going forwards.
when I asked about it last Sept ....I was told
Currently the algorithms for neighborhood switch are being worked on. Part of the issue is your a TE player and there is not enough to make up all the neighborhoods. This is why you sometimes become stagnant. Neighborhoods are supposed to be blocks of players in about a 3 era spread. I myself have been in same neighborhood with a few others for a quite awhile.