Cherry MX switches could be lubricated but you would have to open them, and to be able to open the plate-mounted switches in the Filco Majestouch you would have to desolder them from the printed circuit board.
Some people have done this with their Filcos... but it is not for the faint-hearted. If you screw up, you could damage the printed circuit board inside the keyboard.
If do you like the feel of Brown switches, another option might be to get a keyboard with Gateron Brown switches. They are clones of Cherry MX but much smoother from the start. There have been some quality control problems with Gateron switches though.