Or something along this. I believe tsm 2 could filter similar to that logic.

There is a lot of retired items now, and a lot of very rare variations, the fact that tsm put up a price on very rare items can only be detrimental in my opinion.

It leads general players to believe that an item is worth what the manipulator inputs, it creates a behaviour that encourages prices manipulation, uncertainties (because we don't have a view on the region counter, how can we know that item x has an accurate pricing ?
it must have enough data) in the end and over time inflated prices remains and it only benefit the greedy initiator of that. I can't think of a positive reason why it could be possible.

10 feels like a very good compromise to me. If an item is listed 10 times or more on a region it means it's extremely rare, but a price can still be calculated, because a price manipulator will likely not have 10 of that item.

There is a LOT of possible variation on current content boe now.
If I'm not mistaken you calculate the market price for each item variation. In a result you have some items with very, very low data.

It creates situations where :
Cruel hope crusher item level 710 = 17.6k region market
Cruel hope crusher item level 710+Heroic = 41.9k region market
Cruel hope crusher item level 715+Leech = 6.4k region market

We can't micro manage each items given the number of item variation, TSM should in my opinion automatize this by providing accurate pricing.

I suggest you group each item variation by item level, like TUJ is doing, to consolidate pricing and avoid having the kind of pricing above. Players are then free to create tertiary stat or socket groups that adds a fixed amount of gold added, just like 25/blue battle pets.

That's how you calculate battle pet market price, I think you should apply this to gear with variation.

Letting us check an option that would make the TSM prices behave on some logical rules, such as, the Mythic Warforged Speed Socket BoE will always cost equal or more than the Warforged Mythic BoE type, that kinds of things. TUJ is often accurate on that type of things, while prices from TSM are strange because it makes avg out of very low quantity (for instance there were a Magic Rooster on EU listed for 18k few months ago, so for TSM the region price is 18k, which is true, but obviously not coherent).

Hope it was clear. I know this might not be the intended purpose of the system but that's just a suggestion :p But for me such option makes sense.