On average, you need 2453.4 attempts to complete all meridians. This means you need 49.068 days on average, assuming you get 50 tries each day.
There's no simple way to do this. It's easy to change the overall stat multipliers (for example lowering it by half for each step, so it would no longer become something which really matters for end-game character), but everything else is hard-coded and changing it seems to be more difficult than I initially thought.