Should we for sure be adding the extra Waystone modifiers to our completed temples?

It would be nice to see the waystone modifier derived from the medallion separately from all the other modifiers. Like colour coded or something. At least I'll know what mod I'm dealing with.

Yes. Modifiers add rare monsters/base temple rarity/pack size/number of packs which all increase your loot drops. The chance for rare monsters have +1 modifier as a roll is also big for loot drops. Separate instances of the same mod (increased rare monsters/rarity) appear to be multiplicative. If you hold the map overlay button (not the temple map screen where you see medallions) in the temple to see the full list of mods, you’ll notice that a temple with 1-1.5k% increased number of rare monsters can actually be over 4k% because of the waystone mods. If you can’t run a full mod temple with a group then play solo or don’t do extra mods and hope the increased drops from group play will compensate.

ye

I would've loved to understand that medallion, too. I tried it 4 times. It added chilled ground every single one of them. Never done it again.
I didn't feel like it ''boosted'' anything at all in the temple.

That's one of the things I hate the most about this game: no explanation at all about A LOT of mechanics.
I know I might be way too dumb for some stuff, but this one isn't one those things in which I feel dumb, I just feel like the info is not there. Like when they changed the description for the medallions and ''for better understanding'', but in reality they simply changed how the drops work.

Tell me about it ill be running my temple just fine breezing through until some absolute mad lad of a rare gets spawned that absolutely stonewalls me

Absolutely you should add it without even asking.

Out of interest, does anyone know if leechers can activate the architect fight?

I have a perfect 76 room temple which would be fun with leechers but dont want to risk them breaking it