I think the coin problem is one of escalation.
-Rent was reasonable.
-Ranks were added, and turned into a massive coin sink.
-Ranks were a bit too expensive, but instead of fixing ranks by making them cheaper, new zones were added that made farming coin even easier than before, and some old locations were buffed (for example, toede coin increased to ridiculous levels).
-Now we have enough coin to easily pay for expensive ranks, but as a result rent is insignificant
I'm in favor of a "less is more" sort of fix. I remember one wipe where swords cost 600 coins lore scrolls were 25,000 coins, then the next wipe everything was cut down 100 fold in cost, swords were 6 coins, lores were 250, and mob coin drops were 1% of what they were previously. The numbers are getting so high that maybe this needs to happen again, maybe not a 100 fold reduction, but reduce the cost and coin drops to 1/10 current values, double rent, and then we have a decent economic base.
Also, rent feels very arbitrary sometimes. Some store bought weapons from haven or solace actually have really high rent costs. WHY!? And then there is stuff with rent costs so low it might as well be free, but it's not. Some food items are 0 rent, some are 1 rent, this makes a huge difference if you like to horde large piles of food.
IMO, the whole rent system should be revised. #1 change: remove the "discount" for wearing or equipping an item. It's an idea with the best of intentions, but it just encourages storage characters and mixing of gear among alts.
Store crap, unlimited and sold in major towns- 0 rent. Is there really any good reason why scrolls of legend lore need to be norent, given how easily you can walk over to the shop and buy them?
Unlimited items not sold by stores- low rent, like 25, 50, 100 per item depending on power level.
Limited items with relatively high limits- 100, 200, 400, 800 depending on item power level.
Limited items with low limits (4 or less)- 1000, 2000, 4000, 8000 depending on item power.
Unique items, limit 1- 25000 coins per day. They are worth it. If you can't afford the rent, just use them as norent items, repop them next time you play.
And then finally, remove the fuzzy math. You know what I mean "it will cost you 1000 coins per day you have 4000 coins you can rent for 12 days." WTF is that? If it costs X per day, charge X per day, if you have 1000 coins per day rent that should be 4 days worth of rent if you have 4k coins.