There are complaints about the re-gridning of keys in the Night Market, from myself included. I believe that ZOS intent on the re-grind was to keep players enagaged with the overland so that there would be people always there to group with. It's a good idea, but had the downside of a grind that feels like a job.
Yet, there is a mechanism that would achieve the goal of keeping players in the overland, and could also be extended into other zones (that are now dead) giving newer players an easier time as there would be people there to group with or assist on the harder things like WBs and PDs. The mechanism that already exists - Bosses dropping trade bars.
If ZOS were to increase the amount dropped it would keep players engaged in the Night Market overland. Not to be greedy there could be a cooldown and/or cap imposed on the number that can be earned in a given week/month/season this way. Something like 1 for a Brazen, 5 for an Argent, 10 for a Calamitous and 20 for a Skirmish. This would give all players a meaningful reward
Extending this out into the other zones and tailoring the amount dropped depending on whether it is Base Game or Chapter/DLC would be a reason for players to return to those zones en-masse. Something like Base Game; WB 2, PD Boss 1, PD Group 3 and doubling that for the (what are) more difficult Chapter/DLC ones.
They could even run bonus events for certain zones if they want to drive engagement to a specific area.
(Numbers are for example purposes only)
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Never get involved in a land war in Asia - it's one of the classic blunders!