As for offering an advantage for a streak of bad luck: some games use RNG mechanics where the actual chance is lowered each time it is successful, and the chance increases each time it fails, resulting in statistically same probability but reducing variance.
I don't personally want it, as it doesn't feel true to how a d20 works. But overall it isn't a bad RNG system.
That would break the way terrain, facing/flanking, and the Advantage-Disadvantage mechanic work together in the game. Why should a phase spider on a web higher than the player party lose that height advantage on subsequent dice rolls, just to make it easier for the player to hit it? It's up there for a reason.
They could also implement an easier difficulty mode where you get guarenteed successful rolls every now and then or something along those lines. Just throwing ideas here
It's rumored there will be different difficulty settings, so they'll have to use some way to make it easier or harder. Probably with adjustments to enemy and player HP, or something simple like that. I suppose they could add modifiers to artificially narrow the gap between the two dice rolls on Advantage-Disadvantage checks, but again that would mess more with the basic game design.
