Velvia has been around for a long time now. It is very rare for people to express frustration with it. Truth be told, it's not the film, but the photographer.
80% of your shots go into the bin!? Jeez. A clue is in your film format: 6x12 in 120 format; is there any light fall-off which gives the perception of underexposure?
I wouldn't mind using RVP50 with a Chamonix LF set up; I know of a few who use various LF setups with RVP50 and its uber-saturated Disneychrome brother, RVP100.
Velvia is the best film for the landscape job (and for printing, too!), in lighting that you are able to judge and mould to the film's response. The latitude of 3 stops is fine. Trouble starts when photographers use Velvia in conditions it was not designed for; for the record, it performs best in diffuse illumination, not point (e.g. bright sunlight where there are deep shadows). This diffuse illumination design means that both highlights and shadows can be well taken care of without losing one or the other. Swing the other way to mid-summer sun and you will lose any skerrick of highlights and have nothing to speak of in shadows. People do that, of course. If that gives them kicks, well and good. But it's film wasted.
Photographers have had ample time to learn the tricks of mastering Velvia. Casualties are rare. If people move away from it, it's because of processing difficulties e.g. the distance to or absence of an E6 lab; they fall back to C41 emulsions or B&W. I have been using it since 1994 in 35mm and 120, printing to Ilfochrome Classic (which presented its own nasty problems) and latterly RA-4 hybrid. There is truth that the more experience and skill you have, the better you are able to achieve what you desire. Don't give in! True, also it's easier to get exposures correct in MF and LF, but exposures will always be a bit more challenging in 35mm because of all the contrast squezed into a frame the size of a postage stamp and that you are allowing the camera to make critical decisions when scenes are not as straightforward as they first appear (Galen Rowell wrote extensively about this many years ago), so dump 35mm. And all my 120 work is multispot metered (I bypass the TTL meter on my Pentax 67). I never use grad. filters, but almost always use a polariser for my rainforest work.