What are Engines' targets when it comes to time and level?

The first step to addressing the leveling progression seems to be determining what the actual desired result is, and to that end I have a few design questions.

1. 1. How long IRL (weeks/months/years/etc) should it take for the average player to reach 100 in their top skills?
      
   2. Are there smaller targets along the way, for example hitting the 30s after a week or month?
      
   3. How much more quickly will a power grinder hit the 100 mark?
   4. How long will it take for a casual player, who can do about one dungeon per evening?
      
2. How many hours per week should a player put in grinding to meet the above goal? Or how many dungeon runs?
   
3. How many times should a character need to run the same dungeon or groups of dungeons to progress to the next level range?

I believe that if we knew these few answers, players would be much more capable of determining whether they are experiencing the desired progression  or not, and then could begin to address deviations from the desired timeline.