I think it's a great way to have the competitiveness, without it being a requirement. If you don't want to do speed runs to place on the leaderboard, then you don't have to, and if you don't you won't lose anything of value. It still keeps with ANet's philosophy of everyone can do everything without content gating, but keeps a sense of competitiveness in there for those who want it, but doesn't reward them with anything other than bragging rights. The key would be that those who did take part in say Challenge Missions, they wouldn't gain anything extra from it other than being able to say they did it and point it out through leaderboards. If you put ANYTHING in there as an exclusive incentive, you then lose the entire philosophy that ANet has been working to create.