Many similarities to your situation. My last bike was also a V45 Magna, mine was a '95 that I put about 40,000 miles on, but really wanted the shaft drive (no chain maintenance), fuel injection (no carb maintenance), big fuel tank, and beefier brakes (all Magna weaknesses, in my opinion). Bought my 2014 Valk in Jul 2018 I should have traded up about a year sooner, but the prices really fell when the 2018 Goldwings came out with an updated new motor. Previous owner bought it new a year before and put only 1,200 miles on her, as 3 kids didn't leave him as much time to ride as he thought, so I had the factory warranty on it but of course I never needed it. I paid $9200 (had a luggage rack, sissy bar an highway pegs) and prices went down since then, but they're also not as easy to find. Compare pricing at Cycletrader.com. My neighbor trailered one back from N Carolina when he found a 2015 last year.
Biggest difference is how much smoother it is than the V4, which is also pretty terrific machine in it's own right. Get someone to show you the nickel demonstration, it freaks people out!
The first ride, I was surprised how heavy it felt compared to the Magna - I could barely turn it around in the parking lot, but after a couple rides, it suddenly began to feel very nimble, more like a sport bike in the corners, versus the Magna or the older Valkyries are much more stable/rigid at any specific lean angle, the 2014/15 Valks are much easier to move. I rode her home on I20 with not windscreen, which was a challenge to hang on with traffic going 80 mph and all that wind in the chest, so that was the first thing I bought. Then Corbin seat and Corbin Saddlebags. Wanted an Ultimate seat, but (as KUGO pointed out), they were only making them for the older Valks at the time, not sure if that has changed.
Another big difference, when putt putting around in last gear on the highway, you don't need to drop if 2 gears to take off. Drop it one gear and you'll be at redline before you know it. This machine will start off from a dead stop in 5th gear, and 1st gear is useless except in a parking lot or pulling into the garage, or riding 2 up and pulling a trailer. I heard of one guy in the DFW area who only uses 3rd, 4th and 5th gear! It also has a function that will automatically increase engine speed to try to avoid a stall. I was able to observe it kicking in when testing it on a hill start, but I didn't try to push it to find the limit, as I like her too much to try to force a stall.
There's also no comparison between a relatively new suspension, and one that is 20 or 27 years old, which leaves you a lot less tired after a day on the road. You're going to love that too!
One negative is all of the plastic pins and parts, like the black fuel cap cover flap (at least on the blue model), which is VERY easy to scratch and constantly looks you right in the face forever after.
Think about the battery for any week-long trips, as it is probably a 2015.