I think that all of us (myself included) are prone to heap the fault on the arranger, and then we go and hear someone else playing what we just put down, and it sounds GREAT...

Most of it IS the player, and their familiarity with their gear. Sometimes sounding exceptional isn't so much a product of having an exceptional keyboard, but in learning what your own gear DOES do well, and doing ONLY that, and learning what it does NOT do well, and NEVER doing that!

That way, you sound like a genius! But trying to shoehorn something that does not have styles to your taste into something that does can often be an exercise in futility. Pick the gear for the way it sounds best on the music you play the most, and then simply let it dictate to you what else it can do, and your audience thinks you are great. Try to make it do something it sucks at, and they (and yourself ) will blame you for it!