enjoying888

I was wondering how I could increase demand in my city of almost 200,000 it's on a medium sized lot 100 percent zoned mainly high wealth and medium. One issue is that atleast half of the high wealth buildings are downgraded to medium. Another problem is residents is maxed out on all of their lots almost all high density maxed out. Every demand is negetive I do not allow low wealth and dirty with taxes. My commercial is stuck on places like ajjanagadde inc and high rise medium co. My city has very few avenues and I recently added a grid layout subway station to fix commute. I've tried adding landmarks Colombia center and the living mall they didn't help. My city has a stock Echange and convention center. Every once in a while the medium wealth demand skyrockets and another medium wealth skyscraper squeezes into the already dense residential zones. The only way I can get demand to rise Is to make a disaster like a tornado destroy some blocks of high tech and they rebuild causing the demand to rise but only for medium wealth. Anyone have any tips