They're too skinny. The ratio of height to width is excessive, from a safety point of view. (And arguably, from an aesthetic angle as well.) It's all too easy to smash an entire floor with an airplane. And if a floor below you is obliterated, you can't go around. No alternate routes. You're cut off, just like that.

If we're going to have a building that tall, it should occupy at least two entire city blocks. Just run a tunnel through the bottom for street traffic. This'll cut down on daylight, but we can ameliorate that with light pipes and mirrors.

And have firewalls separating floors into sections, each section with its own stairwell and elevator cluster. You can never do too much to slow the spread of a fire.