Your preference of style is a perfectly good reason to stick with 35mm and I believe is puts you in a rare class. "A person who knows exactly what they are trying to get and how to get it." In a sense you have a fully developed business plan.
The biggest problems most of us have in picking formats, camera systems, lenses, viewfinders, films and developers, papers, toning, etcetera, is that we don't all know where we are going or how to get there.
I do enjoy HCB's work and Erwitt's and Steve McCurry's.
But I also find that I truly enjoy prints like Karsh did of O'Keefe, Hurrel's portraits, and Phil Borges' work. These styles require different tools and a different sensibility.
Simply switching from prism to waist level finder on my RB changes the way I see the world and the perspective I shoot from. Yeah my F5 can technically do the same thing but I can hardly see the screen at my waist let alone focus.
Yes, indeed. Except I am not as confident in my 'style' as you think...
Gotta pick a camera that suits how we work and what we're trying to accomplish. I like shooting landscape with my Hasselblad, because I can use a waist level finder or a 45 degree prism to get really close to the ground, which is how I like to shoot landscapes. And I like the square format a lot. Plus the Hasselblad sits VERY sturdily on the built-in swivel ball mount of my Berlebach tripod. I don't need a tripod head, so it sits very low and is sturdy even in very high wind, also due to the compact size of the camera. Perfect for me.
The 35mm is a great choice for almost everything else, because I shoot a lot of hand held where I can just hold the camera up to my eye and fire away. For portraits I try to use an SLR with super precise focusing, and everything else that is more casual, around town, street photography, and so on, is done with a rangefinder.
None of those decisions regarding film format has anything to do with print quality. The quality is, for my taste buds, more than good enough from 35mm to shoot landscape and print big. If my 35mm cameras would lower close to the ground as easily as the Hasselblad, and would shoot square photographs, I would just as happily use them for landscape photography.
But that doesn't mean I won't use the Hasselblad for portraits (I have one series where I wanted to get out of my comfort zone and used it exclusively for a range of portraits), and I have shot a fair bit of landscape with 35mm, just to prove a point to myself that it can indeed be done.
But anyway, I think the discussion surrounding print quality sometimes gets absurd. While it's true that a larger negative will give a print that is possibly more lifelike with smoother transitions of tone, and more well defined edges, a photograph is always a manipulation of reality, so it's better to aim for what we think the photograph should look like. I think we have to try to figure that out first and then choose the tools to accomplish that. But it also has to fit the method with which we photograph. That compromise is often hard to negotiate.
Back on topic, a 645 rangefinder is a fun camera to use and great for walking around. If you find one that takes 220 film you can shoot Portra and have over 30 frames per roll, which is exciting if you enjoy the larger negatives. The longer lenses will, however, be more difficult to negotiate in dim lighting, in combination with the smaller maximum apertures. Some of that can be remedied by shooting Delta 3200 for example, or Portra 800, or even Provia 400 pushed a stop if you can find it...