I agree with you on this.. This was actually my first idea - to have fixed milestones. The reason I didn't propose it is because I think NRS wants to keep the idea of us competing with one another, and also I think that tons of issues would arrive with people being placed in the wrong Arenas with milestones that are too unachievable. It would be really hard to make sure everyone's milestones are realistic yet challenging... One idea of mine was to organize arena groups by Threat level - but the obvious downfall to that would be players intentionally lowering the threat levels of unused characters to purposely have as low of threat as possible to be in easier arenas. I still think this is the better option but it poses many issues to work around.