If you look at most of the problems in the country at the minute the root cause is housing. Rents are too high, wages haven't kept up, not enough houses being built and mostly a finite resource being used as a basis for our economy.
I think there's a simple solution, a two pronged system. Option 1: If you rent out one house you pay 20% on income and then for every house after that an addition 1 percent up to 80%. So couples who have got together or people who've inherited etc and have a spare house (and don't want to sell yet) can make some money but they'll not get massively rich and are more likely to want long term tenants that will look after the place. What it will do is dissuade people buying up lots of houses who then get rich off the backs of other people working without having to contribute much to society.
Option 2 is if you do have lots of houses then you can become a charity. You don't pay income tax BUT you cannot earn more than 10 times minimum wage (£216,736 a year) and you cannot charge more than 10 times minimum wage per week rent. (Say for a 2 bedroom house) Obviously there would need to be some tweaks for bigger houses and HMO's but you get the principle.
Finally, housing benefit should be reduced to a flat rate across the country (over a period of say 5 years) of 10 times minimum wage per week. The money saved could be used by councils to build more social housing under the proviso that it cannot be sold off and to pay more housing officers to inspect bad landlords.
Basically my plan allows people the freedom of choice. If you believe in unfettered capitalism that allows you to set market rates that squeeze people until the pips squeak then you can have it but in doing so you will be giving back to society. Or you can make a decent living that positively helps vast swathes of society.
YABU: Market forces and the profit motive are what makes this country great.
YANBU: Secure housing should be accessible to all for a functioning society and not a way for a minority to get rich(er) off the hard work of others.