The difference in weight and size between a 5x4 camera and a similar MF field, technical or monorail camera is often not that significant and a 5x4 camera will have more long term flexibility because you can shoot MF with a roll film back or 5x4.

I don't find carrying my Wista 45DX around any more cumbersome than a MF SLR with prism etc which is why I stopped using my MF slrs except for some commercial work over 20 years ago.