Tile sets are essentially different wall dressing for the missions,
i.e. having you run around a sewer instead of a office building.
From my understanding they will be adding even more in I9 with the
start of next years big back ground story arch.
Yep, need to know why you left, and how long ago, and what characters
you had/what style of gameplay you have. Then I could give you a
better idea. Personally I feel the game is getting better and
better, especially with I7 and I8.