One idea that has occurred to me as a "fix" for Reliable Talent is to replace the hard floor of 10 with "roll both 3d6 and 1d20, take the higher." I haven't done the calculations to see what the exact impact would be, but it would make your rolls more "reliable" than without the ability, in that it cuts down on the chance of low rolls without eliminating them entirely, while not raising the chance of high rolls as much as granting advantage would. Plus you can stack it with advantage, and apply disadvantage without canceling the ability entirely.