Yes, the inflation schedule is concerning. Surely, the "value" of tokens given to ICO participants will diminish over time. As you said, at year 3, tokens created during the ICO will only make up 15% of the total number of coins.
Also, providing all that personal information to register for the ICO is a turn off.
While other coins diminish qty in time, this will increase, devaluation usually follows. As I said, if there is money to be made...it is mostly by the developers/owner and maybe just shortly after the ICO. A few weeks after that is likely a continuous downward trend.