I would remove it and patch the floor

IF you keep seating around the island.

The nice feature of the bar height countertop is it minimizes the appearance of chaos in the room. Your kitchen has lots of angles that make the room busy in appearance. I'm not sure that lowering the countertop in this case is a plus.

What color countertop were you planning to replace the black granite with? Here is now the room changes by just changing the color tops.

Is this a new home for you? If so, I’d wait to do anything until you’re sure that the layout works for you.

If you don’t need the cabinet storage, I’d remove the bar height half wall.

Do you keep dishes in your sink/next to your sink in a drying rack - or do you keep it clear of dishes? It is a nice way to hide the ”chaos” as Beverly has pointed out already.

How does your cooktop vent?

Not a new home for us, but I have wanted to change the island forever. My ideal island would eliminate all the angels and just be a rectangle, but with the angeled walls, it is making it very challenging. The countertops will be a light quartz or quartzite. The stove is a down vent.

You might be able to straighten out the island, but there's no way to tell for sure without a floor plan and see how and why they angled the walls in your kitchen.

I would keep the half wall -- it looks like a good place to put out snacks, stage a buffet, etc. I can't imagine any reason that its height would need to change when you change the island. It's a different functional part of the kitchen.