If you lay a 3 foot level on the floor, do you have a full bubble difference? If you spill some water on one spot does it roll to the lower end?
The only problem that I can think of on this "type" of flooring is making sure that the complete back surface of the flooring is in contact with the slab. At some point I would imagine, that your sloping kitchen floor might level out, at that point, there will be the end of the angle and the beginning of the leveled area. At this intersection, you might have trouble getting the new flooring to attach properly.
Since vinyl does give and will conform to the conditions of the subfloor, and wood will not, you might have a problem in this area.
Depending on the degree of the slope, you could float it out to level, but then that has to terminate at some point.
This is something that really needs to be seen before one can make too many assumptions. If the slope is great, then you may be committed to vinyl again.