Repainting a room because one wall is damaged is not necessarily unreasonable if repainting the wall is going to stand out like a sore thumb. There shouldn't be any scuffs on any wall anyway, I have lived here 17 years and never scuffed a wall, I don't recall ever doing it in my entire adult life.
I rent out property, I put a percentage of the rent each month into a separate deposit account to refund the deposit at the end of the tenancy, that way I don't notice the pain of returning the deposit at the end of the agreement. I also write into the agreement that a deduction will be made for professional cleaning all the air cons at the end of the agreement and replacing the water filters in the Reverse Osmosis drinking water system as both activities were done prior to the tenant moving in and are really consumables. Air con indoor unit filters should be cleaned every 30-60 days, I do that in my house, how many tenants ever do it? My experience is zero.
What every landlord wants is a tenant who stays long term, I have never understood this thing about moving to a new property every 6 or 12 months. A lot of landlords don't refund deposits because they can't afford to, it's just a symptom of them being incapable of managing their finances properly. What really riles me, is agents who continue to rent out properties of landlords who serially keep deposits. In my book they are jointly liable.
When my tenants have a problem, I move heaven and earth to fix it as quickly as possible. Every landlord wants good tenants and every tenant wants a good landlord.