.... for every dance the 'caller' is spending over 10 minutes explaining each dance - 
​This brings to mind a quote attributed to Blaise Pascal: 
  Je n’ai fait celle-ci plus longue que parce que je n’ai pas eu le loisir de la faire plus courte.

Roughly translated as 

  I have made this [letter] longer than usual because I have not had time to make it shorter.

In called-dance context:

I am taking too long to explain this dance because I haven't invested the time to discover the best way to describe it.

A couple of notes to myself:

A dance walk-thru is rarely the time for a history lesson. [Although a rare short amusing anecdote before the start of a walk-thru may occasionally be forgiven.]

If you come up with a really cool analogy -- for heaven's sake, don't use it! [Teaching a ricochet hey in terms of slices of pizza comes to mind.]

Chose the right word for the occasion.  Before a balance and petronella I say "make a ring" not "make a circle" because if I mention the word "circle" most dancers will start moving [to the left!]

Do not teach to one couple or one gender/role unless you identify them.  "Swing your neighbor below" only works for the actives.  With luck the inactives will translate, but they may well be looking below for the neighbor *they* should be swinging.  "Ladies start a Mad Robin." leaves the gents standing still when they should be moving.

Do not teach to individual dancers or even sets.  If, for example, you say "ladies chain" and all but one set does it, do NOT simply repeat "ladies chain".  The ones who dutifully followed your instructions the first time will do so again leaving EVERYONE confused and in the wrong spot.   Instead say something like "you should now be on the side of the set with your partner" then pause to let them sort things out -- with possible help from the experienced dancers around them.

Speaking of experienced dancers:

Trust your dancers, but give them a chance.  Watch the entire room.  If you see some ad-hoc teaching going on, be quiet and let it happen. [up to a point -- determining the point at which you step in and reassert the fact that you are the caller comes from experience.]

Have fun and make sure the dancers and the band know you are having fun.   If the dance is executed perfectly by dancers who are annoyed or insulted, it's a failure.   If mild chaos ensues but (most) everyone is enjoying muddling thru anyway, life is good.

Dale