Yes, it is important - the Novak patent (now patently expired) describes the frets on paths that all meet at a common point; a method for making a multiscale board that will not intonate properly.
For the most part, it is no more difficult than that - provided you lay out the outermost scales parallel to the taper (you want the scale length to apply along the string path rather than parallel to the centerline like a straight neck), so you need to know the board taper accurately ahead of time before you can lay out the scales (which means - listen up newbs! - you need to know which bridge you're using right from the start!) - hard to describe in words, once you lay it out in a CAD program it all comes together. Whether you lay out the nut as "equal centers" or "equal gaps" the difference on the scale lengths is negligible. There are some minor tweeks you want to take into account regarding compensation, but these are no more difficult to figure out than on a straight board.
Easy enough on paper - getting the slots on the board correctly is the trick.
On the boards themselves - I have found it is not too hard to get used to them, particularly if you make the "perp" somewhere around #7 to #9. My 8-stringer has the perp at #12 and I would have liked it better at #7. For many chording things, I find a multiscale board to be actually more ergonomic than a straight board.
On the trademark business - don't go nuts here, no one will send you a threatening letter for just using the word - don't go all Pilotjones on me and start with this f*nned fr*t BS like big brother is reading your post And because this is a trademark, technically what you're not allowed to do is to use the term in the formal name of your (for sale) instrument. Like "Erikbojerik Multiscale"....or "Erikbojerik Fanned-Fret"...those could be a no-no in the country(s) in which the trademark is registered. But such a trademark does not prohibit you from using the term as an adjective to describe an instrument. Like the "Erikbojerik's GBO V8" which is "...an 8-string multiscale guitar with an ebony drop top blah blah blah..."....that sort of usage is perfectly acceptable and legal, even if I did want to sell it (which I don't).