For me, a good exchange should have a simple yet nice website design, fast respond to customer support, friendly staff, secured wallet, and low trading/withdrawal fees, I'm a small-time trader so I want to save any profit I got from my investment.
You have said it all, the Op might just have to compete with some exchanges, because when it comes to trading fee, I am not so sure he will be able to compete with some exchanges like Binance, before he will be able to talk of low trading fee, he must have really gotten enough volume that will assist him in deciding on reducing the fee, which usually take lots of years.
Anyway, he can compete with other attributes, such as the ones you mentioned and I am sure that if he tries his best, the sky might decide to favor him and be his limit.