Here's what I prefer after years of shooting:
Scenario A - Nature Travel: Zoom all the way. Good luck driving ten miles in a blizzard to get closer to that mountain range. Or that rainbow, or backing up to get those stormy skies and that river. The 24-105 L is IMHO, on both crop and FF, the greatest nature travel lens you can buy.
Scenario B - Urban shooting: Prime. Faster when the buildings block the sun. Light, portable, inconspicuous.
Scenario C - Indoors: Prime. There's no substitute for 1.4 -2.0.
Scenario D - Wildlife: Prime. If Canon's 200-400 is as sharp as the 500 or 300, I'll change my mind. For whatever reason, wildlife photos just look richer with a good prime lens. Also, I'd much rather shoot at F4 than 5.6 when you get into those dark shrub/forest backgrounds.
Scenario E: Wide angle landscape: Zoom. I know the primes give better detail, but shooting this way is a pain. Nikon showed you can have amazing wide angle sharpness, hopefully Canon can match. I love prime lenses, but I really dislike shooting landscape with ultra wide primes. Lots of tripod maneuvering, adjusting, cropping, cloning, etc.
Best of luck with your decision. You may want to consider renting a couple primes and zooms to help make your decision.