Rolled stats (no rerolls) = default array = point buy. The math of this was all hashed out in 3E play test and again in 5E play test.
Rolling stats is a nice way to surprise yourself and play against archetype; maybe your wizard is strong, perhaps your rogue is wise.
They might even unlock stats and simply let you replicate your favourite TT character?
Multiplayer gets trickier, maybe give everyone a 'save array' button and let them reroll like crazy for a minute or two? So long as everyone is within the same ball park, it'd be fine.
