Loot filters in LE are pretty good and not too hard to use. However, it’s complicated for a new player to know what can be good or not, especially where it relates to which affixes might be useful for leveling. My idea isn’t to change the filter at all, since I consider that work on that has been pretty great.
My suggestion is to create embedded template filters into the game so a new player can simply choose one of these out of the box and figure it out as they go. Basic stuff like a mage/primalist/etc leveling filter, maybe a basic filter more focused on other stuff, like cold damage, minions, dot, etc.
These wouldn’t go into huge fine tuning that endgame builds (sometimes) provide. It would be a basic thing that will hide useless things and highlight a bunch of useful affixes. Plus some rules where you get x out y useful affixes like many filters use.
This would achieve 2 things, imo:
1- Casual players will have a working filter out of the box and they wouldn’t have to search the web for one, which can be a bit daunting for new players.
2- It will provide useful rules templates which they can easily examine and change to their liking
Once players have these filters they can then fine tune them or just stick with it, but they wouldn’t need to search outside tools for one.
As for the filters themselves, maybe have the community participate on which templates would be the most useful and what each should have. I think we should have at least 5 broad filters, one for each class, and maybe a few more, one for each mastery and maybe a few for the more popular leveling builds.
The point of these templates wouldn’t be to have an optimal filter for leveling a mage or a runemaster but rather a sort of simple filter with the most useful/common options almost all filters have. Just a starting point, really, for new players, which might even be useful for older players while leveling.