I just learned that Cruise West also has a "service charge" they tack on which covers basic gratuities. One can also tip more if desired, of course. Tips on this small-ship cruise line are always pooled among the crew.
The trend certainly seems to be toward required tipping, automatically added to shipboard accounts. It's a lot more convenient for the cruise lines, and the crew don't have to go around with hands out and hope they don't get stiffed. Let's hope at least the luxury lines maintain their policy of no tipping!
I can't see letting the way gratuities are handled be an influence on what cruise line I'll sail. I'll bet 90% of the time the actual dollar amount will be nearly the same.
To me the architecture of the ship, the itinerary, the service and amenities on board are all more important factors than whether the gratuity is automatic or not. Of course, I almost always add to an automatic gratuity.