Hi OP! Wow you guys are such a fortunate Disney family! We just got back from a Land & Sea in May, and I have to say, I absolutely THOROUGHLY enjoyed my time on the Magic! I was completely entertained! However, we were less over the moon for the state of the rooms. On the other hand, the updates to the public areas and restaurants were nothing short of stellar. I think the best thing to do is read through our Trip Reports. Mine is just a 4 day, but I saw that there were some including Transatlantics, which might be similar to the longer cruise you are looking at.
Here's mine:
http://www.disboards.com/showthread.php?t=3276365
The question becomes what is more important to you. Having spectacular dining and service, laughing til you hurt, and going back to a comfortable bed and room but maybe the shower is showing its age, or the faucet is leaking? I've stayed on nicer ships on other lines and had a horrible time because we couldn't even get waters or coffee filled, or there were lines for everything (even self serve ice cream!), so I can attest that a beautiful new ship isn't everything for your cruising experience.
Unfortunately, there is only one choice if you want to cruise on Disney's standard level of cruising and cruise Europe, and that's Magic. The same goes for Alaska. In these cases, you get the smaller/older (but often times just as beloved) ships vs incredible itineraries.
On the other hand, if you are cruising for the stellar ships, there is no doubt that Dream and Fantasy are it! But as you mention, they become more of the destination instead of their sometimes 'been there, done that' itineraries.
We actually loved our Bahamian Dream so much that we specifically picked the same exact itinerary to come back on the Magic, plus a sea day. Our experience in Nassau was that good. Plus if you cruise Europe, you will not get to go to
Castaway Cay (I think? Some of the TAs do, I think...) so that is something to consider as well. When it came down to it, our Dream experience was just a little better than our Magic, with the condition of the rooms showing more than perhaps anything else. Guest Services worked hard to resolve our concerns. I also ate better on this trip than I have on any other single trip of my entire life, as everything was set in advance for Gluten Free and I have never indulged so much and not even been so sick on a trip in my life. It was totally freeing!
For our family trips, we have decided that we just enjoyed the newer ships too much to spend that kind of expense to go on the Magic for a European destination. My next goal is to get on the Fantasy, the most beautiful ship I have had to tail back and forth on our last Carnival. We enjoyed the technology upgrades in the new ships (although the animation dinner show at Animators Palate on Magic makes a very, very strong effort to match the Dream and is the same as the Fantasy), but we liked the interactive 'alive' feel of the Dream vs the Magic.
I guess if it was me, I would dip my toes into a
Disney cruise before I jumped into a major destination, IF the ship equals a big part of your enjoyment. If on the other hand, you are dying to give Norway a try and don't trust other cruise lines (which can be a warranted concern if you know you like Disney's standards of service), then you might be happy taking the Norway cruise on the Magic. If it was me, I'd try a week on the Fantasy first if I could afford it, and if not, I'd take a 4 day on the Dream and go back to Blue Lagoon which was already perfect for us anyway!
I hope that helps?