Your profile says Seattle. The weathering of the wood says that you get a fair amount of water.
That slab is too high relative to your siding and probably the threshold of your door. Modern code says 4" from top of slab to top of impermeable layer.
If you are keeping the house for more than 10 years, I'd ditch the slab, set the grade to the correct height, put down landscape fabric, throw down a layer of sand, set some pavers and then lay down pressure treated sleepers and composite decking on top to match the height of your door threshold. This should improve drainage, reduce splash back, minimize wicking of water into your siding, minimize damage to your wood post, help deal with potential snow accumulation near wood.
While you are re-grading put down some conduit before the sand/pavers so you can run low voltage patio lighting later.