Multiparties only work even then it’s as you say a CF in a parliamentary system. It would take a major constitutional change. Basically it would mean throwing out the constitution and starting over.
here we have parties for
left wing, i love the arabs party
askenazi ultra orthodox party
sephardi ultra orthodox party
a hodgepodge of arab parties united under one umbrella
a secular russian party
an anti-religious party
a hodgepodge of right-wing, zionistic, religious “settler” party
likud (currently the Bibi party)
labor (old school kibbutznik socialist party)
at one point there was even a pensioner party (for old people)
if you cant find what you’re looking for or need, just start your own party like Ariel Sharon did in 2004!
did I miss any?