Crit is fine, but to know whether base damage increase or crit increase will do more damage, you have to actually run the numbers. There are certainly times in D&D where more crit is better than more damage, depending on the situation and the figures in question. But that's why we ran the numbers, and mathematically proved that while sometimes "accuracy do more damage than raw damage" in this case it definitely does not, thus the massive increase in average damage with the other config. You can say "great sword mastery don't do more damage", I can *prove* that in this case it does, substantially more, and have already done so. It also on average adds far more damage than Savage Attacker *even if you never have the passive turned on* due to gaining the bonus action attack on a crit, which is just fundamentally more valuable than +2.5 damage on a crit. When getting attacks with an average damage in the 30s, you can have 3, 6, or 9 attacks in a turn, it doesn't matter. Getting an extra one will be more valuable than an extra 2-2.5 damage per attack, and the more attacks you get the more likely that crit becomes.
It's not complicated to figure out when it should be on or off, either - if (percentage to hit) * (damage with it off) > (percentage to hit with it on) * (damage with it on), then don't use it, otherwise, do. In this case it's a matter of going from a 97.75% chance to hit if it's off, but dealing 31 damage (45.5 on a crit) for an average damage of 0 + 45.5 * .36 (16.36) + 31 * .62 (19.22) = 35.5 with it off, vs the 40.5 with it on. Meaning it provides an extra 5 average damage (15% more), *even without considering the bonus action attack*. So in this fight, it should be on. But you know, you can only really figure it out if you understand and care about the numbers.
