Most still work when out of date. The ones that don't are open source by their nature and can be updated yourself (don't publish without original dev permission). Regarding slowness, these are Lua scripts running, and some require a lot of CPU. Master Merchant, for example, uses tons of CPU when it does its initial guild sales scan when you load the UI.

I recall seeing some API changes on PTS notes that will make profiling of these scripts more robust. That means the developers will be able to see what parts of their addon use the most CPU if they are concerned about optimization.

And a big game-changer for add-ons: The SavedVariables are going to be written during game play if disk IO allows or at next load screen. Mods can request priority for the writes, etc. This is a huge deal for people that use the TTC client to upload listings (because that client checks for changes to its SavedVariables and reads and uploads them when they happen).

Mods that need to store data (like MM and many others) will be way less likely to lose that data upon a game crash. And you also now have good options to run your own scripts that backup these SavedVariables to external storage at regular time intervals. Basically, no more /reloadui and then alt-tab to Minion to make a backup.

Minion should now overhaul their backup features to schedule them at intervals and write to any storage available to Windows (which could include cloud storage, network shares, etc.). That would be nice. That data is extremely important to me. I'd die if I lost my addons and settings. Happened once. Will not happen again even if house burns to the ground.

Well, sorry to go off the rails. But yeah... When an addon author loses interest in the game, they'll probably quit developing for it. You have to hope someone else takes over development or an alternative comes out.