The way mirrors currently work gives a lot of problems. This is because you can only mirror a COLUMN (and connect that column to an item), instead of mirroring an entire ITEM.
This gives the following limitations:
Mirrored columns in other boards do not share UPDATES with the original item. Updates work great for collaboration, should work for
mirrored items as well.
also see: Shared or mirrored updates for connected items - #14 by Nir-Jetpack 1
Mirrored columns in other boards cannot be included in WORKFLOWS for that specific board.
also see: Mirror and linked items don't work with intergrations.
and: Notify a person from a mirrored "People" column in an automation
Mirrored columns do not show SUBITEMS off the original item.
also see: Mirror subitem from one board to subitem in another board - #2 by BiancaT
and: Really need to mirror subitems across boards - #6 by aminat.akhmadova 1
Mirrored STATUS columns in other boards can not be sorted/filtered properly
also see: Unable to sort or filter by mirrored columns - #33 by hdurey 1
Items in general are not unique, making (unwanted?) DUPLICATES possible.
When setting up a new board with mirrored items, you have to MANUALLY ADD ALL COLUMNS that belong to the item, instead of just transferring them automatically with the mirrored item. With 20+ columns, this takes a lot of time.
There are a lot of workarounds (some pretty, some less pretty, some unworkable) and 3rd party tools (paid). To me the mentioned problems feel like basic features a CRM or Project management software should have.
We need to be able to create an item with a unique name (or tag). Copies of this item should still have the same unique information (including “updates” and subitems) and be able to be viewed and edited form other boards. This also makes it possible to automate them in workflows in other boards.