I feel the same here. As a person with 2 level 300+ characters, obviously I would like the rewards but realistically, it's probably greedy to be asking for rewards when you've already gotten them once. It's like asking to get paid twice for the same job done.
I think this occurred due to poor planning. For example, prior to these current changes, they should have systematically added mileage points to all characters in the game that were over Lv. 130, Lv. 150, etc. That way, old players would still receive their mileage points. The only apparent flaw to this is that old players who haven't collected their rewards hitherto this patch would be able to double collect mileage points, but a solution to that is easily found: Just as how mileage points were added automatically in the past, the same should have been done here as well.
Just a tiny insight prior to a patch can lead to many happier players.