To answer your original question...Yes it is!
If you've already decided, then, so be it. If you're not yet firm, consider this perspective...
FWIW, earlier this year, I made a conscious decision to leave behind my D800E system of 3 zooms (between 18mm and 200mm) + 300mm in favour of a 1" sensor Sony RX10iii. Last year, I took the whole kit with me to the Galápagos and, while not regretting it (I'm thrilled with the photos!), I was frequently juggling lenses and carrying significantly more weight in equipment than I really needed.
In Iceland, with lighter gear, scrambling up and down volcanoes and glaciers was so much more pleasurable. I also found I needed a tripod far less than with the FF gear. I wasn't shaking with exhaustion (
), but also, with the smaller sensor, I could use f/5.6 to get decent depth of field, so could use faster shutter speeds. Yes, my DR was less, but a couple of HDR exposures took care of that. And, when the amazingly dramatic, can't-be-missed trophy shot appeared, I shot multiple "stitchable" frames to get the IQ needed for really big (larger than 16") prints. Exactly what Phil suggested.
You see, it all boils down to what you intend to do with the photos. Do you have professional uses for the photos already lined up? Are you selling through a gallery? Will photos of backwoods Norway be saleable in volumes great enough in your home country to warrant carrying the FF gear? Or are these shots for your wall, a photo book, your website, etc.; a few "trophy" shots plus extras to remember the amazing experience of being there? Let's face it; the gear many photographers are carrying around right now has IQ far beyond what they will ever use, unless they are shooting professionally.
After being at this for 40 years with 35mm, 6x7, 4x5, and now digital, I'm only just now finally believing, it really isn't what your shooting with that counts, it's what you do with it. Need more DR? Shoot HDR frames and blend (responsibly!). Need greater detail? Shoot stitchable frames. The only ones you're satisfying with the FF gear are the pixel-peepers (and perhaps your own ego when everyone else shows up with FF! Equipment envy drives many of the gear purchases these days!
I'll make a few "16x20s". Side-by-side with the same shot made with FF gear, one might see a difference. But I've also learned, the only ones who really look that closely are other photographers and they sure aren't buying my work! If someone loves your work, it's because of the content, not the equipment.
If I was to "do it all again" now, I just might pick up the Oly system Kevin raved about recently
. That 12-100mm zoom combined with the updated M4/3s sensor sounds just about perfect. Throw in a wider prime and a TC or 200mm and you have a great, lightweight system capable of doing everything a FF system will do.
That's my experience, anyway. Tough decision. Good luck! Sorry for blabbing on about it.