Regarding the idea of using "mute" as a preposition, I see three objections:
toki, jan Kuka o!
I share objections number 1 and 2 (the third one is over my head at the moment. ).
It appears as if someone wanted to add and remove the expression "lon poka (pi)" (in the sense of "compared to", "when compared to", "when next to").
You have more money than I have. ("Your money is more than mine.")
mani sina li mute lon poka pi mani mi.
mani sina li mute mani mi.
Your friend is taller than my sister.
jan pona sina li suli lon poka pi jan sama mi.
jan pona sina li suli jan sama mi.
The same metaphor ("lon poka (pi)") seems to be (over-)used and abandoned with other pseudo-prepositions as well. This seems to imply using spatial nouns as adjectives, i.e. without "lon":
Your car is standing next to my house.
tomo tawa sina li lon poka lon poka pi tomo mi.
tomo tawa sina li poka lon poka pi tomo mi.
tomo tawa sina li poka tomo mi.
The sun is over the forest.
suno li lon sewi lon poka pi ma kasi.
suno li sewi lon poka pi ma kasi.
suno li sewi ma kasi.
There is really no need to introduce this kind of brevity, especially since it comes with the risk of less clarity (having to consider more and more possible readings). Let's nod politely to the jan nasa that try(ies) to introduce such structures and say "thanks, but no thanks".