I would want to figure out something different for the stairs. Carrying beds, dressers, etc. down a hall with a 90 degree turn only to do a 180 to go upstairs and make another immediate 90 doesn't sound like fun at all. With that big open space, I would want a 9' ceiling at a minimum but prefer 10'+. Taller ceilings mean more stairs.
Take a look at your roof plan. As drawn, the second floor bedrooms don't make sense to me unless the back of the house is one giant shed dormer. Might want to show the fireplace flue going up through the second floor too.
Might want to think about the connection between the driveway and front door. That's a long walk in inclement weather. Personally, I'd go for a front loaded garage. The back of the garage that faces the front door needs something to break up the long expanse of blank wall.
I look for a way to move some square footage from the master bath to the master closet. Never enough storage. Also on that note, having to walk through bath to the one and only closet ***** - have it now and never will again. Might actually look at ways to completely re-arrange our closet to change that and gain more storage.
Where are things like air handlers, water heater, water softener (if needed), electrical panel going in this plan?
Basement, crawl space, or slab foundation? Unless coastal, I'd prefer a basement (and a look out if site grades would allow).
Kitchen needs more counter space. Think about moving the fridge to the end of the island between the pantry and door to mudroom. How are you going to vent the cooktop? Anything overhead is going to block views to the family room.
Entry needs a closet unless it is under the stairs.
I wouldn't want guests going to the mudroom to use a bathroom but at least the laundry has been separated.
Dining room and office need to be deeper front to back. Think about family dinners at the holidays.
Where does the Christmas tree go in this plan? We have a similar plan and it ***** to get the tree up, move furniture to where you can still walk around the room, and be able to sit in your favorite chair while having line of site to the cable box / tv for the remote.
Garage isn't deep enough if plan to store anything on the back wall.
Since this is your "last" house, you should really think about designing for aging in place and what that would mean for you and your family to get the most out of the house as long as you are able to. Groups like the NAHB, ASID, AARP and others have extensive information about home design for aging in place. A lot of the items won't cost too much more (some are free or no cost) in a new build than going forward without that planning.
Look into possibility of a future elevator - frame it to their specs with a section of floor that's easy to remove and use the space on both floors as a closet until you, your wife, or other family member, lose mobility and need the elevator. Future elevator might affect electrical service size.
Install blocking for grab bars near toilets, showers, tubs. A large properly-constructed curbless shower would be your friend.
Mount electrical receptacles a little higher than normal so they can be reached while seated in a wheel chair.
Comfort height toilets (think about the HC stall in a public restroom vs standard)
Lever locksets in place of knobs
Think about setting up one room as a suite for a live-in healthcare provider or family member.
Good luck with the planning and build. Hope to see a build thread as you go along.
