The later in May you travel the more kids will be on board. If you are traveling with your own they will think it is great. Lot's of kids is not a deal breaker but if this a concern for you then I would cruise earlier.
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Alaska 2014 - haven't picked a cruise yet
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012
Celebrity: Summit 2011
Princess: Ruby 2010, Caribbean 2013