It's an interesting idea, IEX basically did something non-random with introducing latency. A consideration is once you do this, the business model of exchanges

It's an interesting idea, IEX basically did something non-random with introducing latency. A consideration is once you do this, the business model of exchanges changes a lot (they make a ton of money on colo). So they need revenue elsewhere, so maybe free retail trading goes away again, who knows.