Here are my take homes for a touring tent ( as compared to a bike packing tent)
Has to be able to be pitched externally, ie the fly can be erected first, without the inner. Makes thing much easier if it's raining when you arrive can set up the inner in the dry or when you break camp, same same. Or if you are on top of some pass, in pouring rain, you can whip it up and have a dry lunchtime.
A vestibule per person, of a decent size.
Good head room.
Lots of mesh in the inner
Decent heavy grade floor
Good high sides on the floor tub so no ground splash through the mesh
Big doors
Large high vents in the fly
As vertical end walls as possible
Lots of interior pockets
I'll generally take a bit of a weight penalty to get the above.
Worthwhile also treating the whole tent, inner, floor, foot print and fly with some Nikwax Tent and Gear Solar Proof. Adds extra water repellency and is a sunscreen to protect against UV damage.
Current tent for 2 is a North Face Talus 3, nice and roomy when you're on the road for a couple of months.