Get more drift wood in branchy, interesting, twisty shapes.
Get some more river rock
Get a lot more plants.
Look at some tank layouts you where you like the driftwood layout & try to emulate it. Even look at binding some of it with java moss, java fern, or anubias, or all three. It gives a lovely natural feel and the fish something to swim around.
If you like your skull_ you don't need to take it out. F*&@! opinionated people who are telling you to get rid of it.
I think you could nicely work it in by more heavily planting the tank floor. (Look at some dutch aquarium setups for ideas.) If you cleverly put the skull (maybe tilted a bit) amidst the planting_ some tall stuff close behind it, some slightly shorter stuff close around it, some really short stuff close in front of it, if a little algae grows on it let it_ It'll start to look less like an ornament & more like an abandoned relic.
Definitely Blackwrap the back of the tank though.