I think it really depends on your family.
For us, we didn't do official excursions, and won't next time. Our son is pretty young still (and special needs, so developmentally he is younger) and we don't always know how he will react to things. We try to just keep flexible, and change plans at a moments notice.
And the practical reason... The cost. I stay home with my son, and we don't have lots of extra money. We save up and spend our money on the cruise. We would rather spend the money for a great
dcl experience, than to spend tons of money doing touristy things in the ports.
In Alaska, we got off each morning, walked around, and found things to do. In Skagway we went to a playground, and took a nature type walk. In Juneau we did end up riding the mt Roberts tram, and then walked the strip. In Ketchikan, we stumbled upon a free shuttle, and took it to the park district and took a walk in a beautiful park, and watched salmon going up a ladder. All free.
We then got back on the ship for our paid-for lunch, and spent the afternoon on a pretty empty ship! It was perfect!
We are doing the L.A to Vancouver repo next. We plan to walk to pier 39 in San Francisco, maybe ride a cable car to see the sights, and come back to the ship again!
When DS is older, we may look into more active things, but this works for us now!