For mythics, I think we're still waiting to hear what the crafting system will look like. Especially for mythics that we've already missed (Famine, are you out there?), that will hopefully put them back within reach. I'm never going to try using event keys to target a kingdom mythic again - that was not a good use of resources.
For Mythics, I've heard that the expected drop rate is about 1 in 10,000 for glory keys and 1 in 1000 for gem keys, so even with your 1300, you might not have been into pity timer territory yet. I really doubt they would implement a guaranteed drop rate at the same level as the expected or average drop rate. It would almost certainly have to be at 2 or 3 times the base number.