No, they shouldn't. They only gave everybody 29/30 for War Supporter because Epic can't always continue to make new events. There's absolutely no point in decreasing the requirements for all the other Onyx medals because they are and always will be possible to acquire.
163/164 games completed (including DLC)
Completion percentage: 100%
Latest retail completion: Dragon Age II
Latest arcade completion: Dust: An Elysian Tail
Currently Ranked #1 on Achievement Completion Percentage Leaderboard on TA