Yes, I've been trying to find one with a sauna and it is such a pain! It would also be fantastic to be able to add conditional amenities. Like if I want a sauna and/or a hot tub. If both are available, great! But if there is a sauna, I'd be okay with no hot tub and vice versa. There is no way to indicate that, so I have to take at least twice as long searching. My eyes hurt! Haha.
There are other facilities/amenities that definitely need to be added as well- steam shower and other spa amenities, outdoor firepit, if there are pets living in the home while you're there... etc. There are a ton of options for "unique stays" and very few for facilities or more out of the ordinary amenities.
On a somewhat related note- There needs to be a way to sort lists! Being able to sort my list of say 25 options by price, ammenities, distance to somewhere, etc. would make it so much easier to narrow it down and book! The list system as a whole is pretty week.