There are probably as many ideas of what makes a good rando bike as there are rando riders, but basically what you've spec'd looks fine in principle.
I'd tend to agree that a frame built for actual loaded touring may be too heavy and brick-like, but some riders prefer that (I am not one of them). My commuter bike is a Surly CrossCheck, and it feels like riding a cinder block. That said, I'm a fan of steel frames as long as they aren't that clunky. My brevet bike is a '70's steel road bike and I love the way it rides.
The biggest factor in all of this is fit. If you've been riding a flat-bar commuter bike, that may be harder to determine based on what you've got. That would incline me toward suggesting something that you can test ride, or at the very least, test ride new bikes whose geometry you can then compare with the Campeur. There's all kinds of stuff that sometimes matters and sometimes doesn't, and conventional wisdom may or may not bear out in your particular case, and there is no substitute for getting on and riding. Try out different types of levers as much as you can; each brand/style has its own shape and in my opinion that's a perfectly good reason to choose which brand your drivetrain is, at least for a long distance bike. If your hands fit better on Campy Ergo levers than on Shimano or Sram, go Campy and use those as your shifters. If your hands fit better on one of the various types of non-shifting levers, use bar end or downtube shifters. Again, more reasons to test ride, even including bikes you know you aren't going to buy, just to try out various components.
One thing to bear in mind re. triple vs. Rene Herse double is the Q-factor, or tread, as Jan Heine would say... either way, what you're talking about is how far from the center line of the bike your feet are. A typical triple puts your feet spaced pretty wide, whereas the Rene Herse puts them narrower than most doubles. It might not matter, but then again, it might. My better half absolutely hates narrow q-factor cranks, and I really hate wide q-factor cranks. My brevet bike and my touring bike both have TA cranks (they look something like the Rene Herse ones) and his bikes have triples. I got the gearing range I need on my touring bike by using 46t and 30t chainrings, and a MTB 11-34 cassette with a MTB rear derailleur. I admit that I do miss having a 53t chainring, but for what that bike gets used for, it's worth the trade-off. If it were a brevet bike, I'd probably go for a more standard double.
I agree with the recommendation of a generator hub in front. In addition, I recommend traditional 32-spoke 3x wheels. You can use butted spokes and light rims to get the weight down if that's an issue. But if you break a spoke on a wheel that has 32 of them, you can use a fiber-fix spoke and it'll be fine. Actually, even if you don't, you can probably finish your ride anyway and the most you'll have to do is open up your brakes a bit or tweak the other spokes around it to true it a bit. If you break a spoke on a low spoke count, high tension wheel, even a fiber fix spoke might not be able to straighten it out enough and there won't be enough other spokes nearby to true it that way. Not to mention that if you get a generator hub, it'll most likely go into that kind of wheel anyway.
Last thing to keep in mind is, if you're just starting out on long distances, it's entirely possible that you'll find yourself changing your setup as you go. You never know what you'll discover about your preferences after sitting on your bike all day, all night, and all day again.