Why be concerned with the "looks" factor. Everyone will have an opinion about how it looks, but who cares? The reason(s) to keep it there or stow it inside should relate to-
visibility- Does it bother you or make you uncomfortable backing up/ driving, and having the loss of visibility back there? If it is a stock spare, then probably not too bad, but if/ when you upgrade to a full size spare, you will lose a lot of visibility.
off-roading- With an Unlimited on tight trails, steep climbs. etc...that spare can really hang-up on things and cause damage to the bumper or tire carrier. If it digs into the ground, it can be the difference between making it through an obstacle or having to be winched out. Again- stock spare not as bad as a 35" or 37" tire.
stowage- Do you have the space inside the jeep to relocate it there? If you don't keep a-lot of stuff in the jeep, then you may consider just putting it inside.
I love having mine not hanging off the back. I keep my 35" spare inside the back of my 2 door with all my trail tools and recovery equip and still have room for a cooler, spare parts, back-packs, etc. I love looking in my rear-view and having a full view of whats going on behind me, and no longer dragging the spare over ledges and into trees.
JMO- but consider those aspects over the "looks" point of view.