Most people will stay focus with coin list and volume because the can't doing transaction without that. Reputation also came from both and if the exchanges want new member to get fresh fund they can release give away/ payment program in their sites. The crucial part is about speed transactions and security program, exchanges is the first place hacker will take action, that's why KYC program ( ID, 2fa ) really needed. Many factor can become good sign to join exchanges but safety is always become member focus and priority.