The Wraith Stealth (assuming you have the non-X 3600) cooler you have is just a simple heatsink, there is nothing to fail except the fan.
Cleaning out all the dust buildup would definitely help things. I think your idle temp is a bit high, but you didn't mention what your ambient temp is.
The high idle temp could maybe be caused by low fan speeds. You might want to check your mobo settings and check what fan profile you're running, and try a more aggressive one (or make a custom fan curve). It could even be that the fan itself is running slower than it's supposed to, so check the fan RPM's.
Plenty of very good choices in aftermarket cooling if you want to spend the money.