How about we get rid of the EW and MW perk farming arenas but keep the EW and MW scoring? Players would have an option to score any applicable ride as early or mid war or keep that ride in the overall MA scoring in much the same way as they would choose attack or fighter scoring.
This would give players an incentive to up early and mid war rides in the sole MA (name in lights on the web page each tour). It makes the perk system work more as intended. Also it concentrates the players into one arena.