Less than a day ago, GGG released Game Mechanics Q&A https://www.pathofexile.com/forum/view-thread/3130696 where map equity system was completely explained.
After carefully considering the implications, I conclude that map equity is a system that completely makes or breaks atlas progression. At the leaguestart, many topics are started complaining about difficulties with progression and map sustain, and I didn’t have any answer to those except standard “roll your maps better”, “get higher map completion” and “use master missions and fragments”. I am sorry for that, but I just didn’t have any better advise. But now, I’ll first ask, does the atlas setup utilize map equity?
When starting Atlas progression, equity doesn’t matter. All map tiers that can drop are either unlocked on your atlas or adjacent to the map you’re currently doing. No potential map drop is converted to equity.
When the Atlas is fully complete, all equity does is increasing t14 drops by 50%.
Let’s consider a player who decides to farm a t10 map (not unreasonable, say, valdo harbies with 2 watchstones) for a while which in their setup is the highest tier on their Atlas, and they completed 100 maps. What they’ll get, on average, from killing enough magic monsters to get 110 maps? Those maps are randomly rolled for tiers so there will be 10 maps for each tier 1-11, then completion bonus bumps all maps up one tier but is limited by ilvl, so 20 maps will roll tier 11. Except t11 maps cannot drop, so they turn into equity instead. Thus the outcome: 10 maps for each tier in 2-10, and 20 t11 maps worth of equity.
Maybe they are a new player, and their watchstones are placed sporadically, so all tiers of maps below 10 are available. All maps that rolled tiers 2-10 actually drop, so the player gets 10 t10 maps. What about equity? It accumulates and does nothing.
What if this player follows a “leapfrog” guide? They remove watchstones from regions they’ve completed. If there are no watchstones in other regions, atlas lacks tier 6 and 7 maps, so map equity is spent turning those into tier 10 maps. Boom, 30 maps obtained.
What if a player that got most of his watchstones decides to farm yellow maps in Valdo’s? All maps from tiers 2-7 are converted into equity, and equity from tier 11s is just enough to drop 60 tier 10 maps instead.
Two players roll maps in the same way, but where one gets 60 maps, the other get 10.
If you had a long streak of bad map drops before, it was probably unfortunate watchstone placement and not an unlucky map RNG streak.