they're both equal because they'd both do 300 damage in two hits
That isn't how probability works. Events don't get more likely to happen as time passes without them happening. Say you flip heads on a quarter 3 times in a row, that doesn't make it any more likely for the next flip to go tails. It's still a 50% chance.
Let's run a simulation using a coin toss, with heads being a critical strike and tails being a normal strike. I flipped 10 coins and the results are exactly 5 heads and 5 tails. There is no pattern to the order of the heads/tails flips, other than that each outcome can be expected around 50% of the time. The sword that does more consistent damage is better in my opinion, because with the other sword, you're relying on RNG which could get you forgeted if the numbers don't go your way. If the randomized sword had more than 50% chance of critically striking, then it would be more worth to pick, but at 50% or below, it's my opinion that the consistent damage is better than a chance of more damage.
TL;DR over 10 strikes, it's 1500 damage either way assuming you have average luck, but why get forgeted by luck not going your way?
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