I'm sure someone will find fault in it but why not have the trial branch with the same rewards? (or even slightly different as i'll explain a lil further down)

branch 1:
The current 5 marrow/ 3 PW item / and void w/e (so then the people who started to gather early can be happy)

branch 2:
something solo or low-man that takes a 'long time' Ex: 5-10k kills with weapon (SE could even throw in a stipulation that doesnt allow you to get a stage 2 through this path, sortof like the fake empy's or something)

This would allow the marrows to still have value, and be the quicker path (given you have the support) to your relic and the people who can't or have a severe aversion to arch dynamis can slowly and safely work out their own upgrade.

Yes this will make it harder to get help on arch dynamis but in so far as i've seen nothing really promotes doing arch dynamis except changing his drops.