As someone who had a planted freshwater tank and a reef in the same room next to each other you should be aware of the color differences. If you are talking a cichlid tank with a 10k light and a reef at 12k it isn' bad. If you're talking a planted tank at 6-7k and a reef at 20k the contrast is very clear. Some people mind, some don't, but it's worth being aware of. I really didn't like it at first, but got over it and nobody I invited over ever minded.
I think you still have the TV too high in the mock up. Maybe I have a stiff neck, but I like the top of a TV not much higher than the top of my head. This used to be pretty standard when TVs were smaller. It looks a bit odd with a big TV until you get used to it, but really does work well.
Pros for 1 sump:
More system stability due to water volume.
Some equipment common (controllers, dosers, ATO).
Easier maintenance/water changes.
Cons:
No fresh water/salt water.
No high nutrient/low nutrient differences.
Longer hose routing.
Larger fuge area/lighting needs balances out lack of duplication.
Larger skimmer needed.
Larger sump volume to handle power off overflow conditions of both tanks, two return pumps, etc.
Personally I'd keep them separate if budget allows, but it depends on your goals for the tanks.