I would like to assume, that at some point, they would balance out the current top tier series with a fourth and final eb in that set. As far as new lands I think they should go back to the first sets of lands and increase the level caps to lvl50 (where lvl50 is inline with current building prices & stats) before adding a new set.
No way are they increasing lower tier cap, sorry. It's a gradual game, you slowly unlock lands and build. They made an exception with OR lands, that was a huge mistake.
It wouldn't be accessible to new accounts. You would have to go through the process and unlock X amount of lands before the level caps opens. Level cap increases are a much more viable way of increasing EoG content without a total revamp of the game or massive updates full of bugs. The OR level increase was a great idea and they were on the right path, but they stopped there.