We did the 'normal' 7 nt Alaskan itinerary in 2016 and loved it--that's the only type of sailings they had that year. When you add Icy Strait Point, your Juneau day is cut short (1PM all aboard vs. 4:45PM) as they combine it with 'Tracy Arm Day.' If there is anyone with motion sickness in your party, it would likely be worse for them with Icy Strait Point as it sails the open ocean longer to get there.
I would check out excursions for Icy Strait Point to see if there is anything there to interest you. Icy Strait Point is a privately owned tourist destination--essentially made for cruise ships to visit. Also think about what you want to do in Juneau and if you'd have enough time to do it with a 1PM all aboard time