It seems like I will need to become very marksmanlike and disciplined with the large format or medium format!
I think you would find discipline and accuracy are advantageous whatever gear or process you are using. Cameras are tools. The tool user should be directing the tools, not the other way around.
Don't be intimidated by bigger cameras/film. It's the same as driving a bigger car. You have to get used to the size, parking might be a little different, but all of the rules of the road are still the same.
I shot 95% of my landscapes on 4x5 film for a decade. Now I'm using a 5D. Is it the same? Nope, it's hard to beat that huge chunk of film for pure resolution. On the other hand a lot more than resolution goes into creating a good photo. I've replaced 4x5 with a 5D, and the photographs I'm creating make me happy I made the switch.
Here's another BW landscape photographer who has switched from 4x5 to a 5D. Check out his article "Farewell To The Revolution".
http://www.huntingtonwitherill.com/
You should try 4x5. It's fun. You'll see a lot more difference between 4x5 film and 35mm digital than you will between medium format film and 35mm digital, and most medium format rigs are just as big and bulky to haul as a 4x5.
EDIT: Here's a link to an almost 3 year old, pixel peepers' comparison between 5D, 1Ds II, 645 Velvia, 4x5 Velvia, assorted medium format backs, and a scanning back. I don't think it's going to take anywhere near 150mp to beat 4x5 film.
http://www.luminous-landscape.com/essays/back-testing.shtml