Either decision would be fine, but putting laundry on an interior wall is just asking for trouble down the line. Dryer vents need to be as short as possible and directly vented to the exterior. Otherwise, you get clogs and a huge safety hazard. And your dryer stops working and you pull out lint balls the size of a poodle. And you're lucky to not have a house fire. I've seen dryer vents through a concrete foundation where moisture collected and made a complet sodden mass with the lint. The homeowner had to abandon that vent and just have ductwork running straight through the master bathroom to the exterior. IT was ugly, and if the laundry room had been sited better, it wouldn't have been necessary. I've also seen dryers vented straight up through the roof where all of the lint falls backwards and clogs it up for an amazing height. Dryer venting is usually an afterthought in most homes. Until there is a problem with it. Which there usually is when a dryer is sited too far from the exterior without a straight vent run. With Jenny's variation, at least you could make the WC wall thicker and run the dryer vent through that to the exterior. You will need to remember that a 4" rigid duct is required and that really won't fit into a 2x6 framed wall and leave any structural integrity left. So, either a 2x8 wall or a small soffit of some sort will be needed.

I am not sure that you have enough room for a sink with two faucets, at least if you intend to have two people use the sink at the same time, because a person's body width takes up enough space to make it impractical unless you have a sink that spans most of the countertop. Trying standing side by side with someone else and see how much elbow room you need. THen figure out the size of the sink you need. I think you will determine that you need most of the width of the vanity.

I have an almost 400sq ft master bedroom including master bath in a two bedroom, 1500 sq ft house. I have a three person jetted tub, a five foot shower with seat, a 55" single vanity. and a separate wc. It's big enough so I can have my dresser in the bathroom containing my underwear/basic wear. So when I wake up in the morning, I can go take my shower, get out of the shower, dry off and put on my basics. Turn around, blow dry my hair, put on my make up. All without ever having to turn on a light in the bedroom and without disturbing my husband who probably is still asleep. I spend at least 25 minutes every morning in my bathroom. One of my must haves during the design was ample space for my hair dryer, brushes and straightener. I want to be able to dry my hair while having my straightener turned on and heating up and I need a dedicated spot for that. At night, my 3 year old can comfortable splash in the tub, recreating a scene from godzilla with dinosaurs and boats while I relax in my recliner and whatch tv, while also keeping an eye on the kiddo because I do not have a door to my bathroom. After the kiddo is in bed, if I want to I can take a nice long soak while watching House Hunters. My master bath is massive in relation to the size of my house, but you know what? So what. It's not "fantasy living". I don't have to live with a child bothering me or knocking on the door, I'm not wasting any space. I spend a lot of time in my bathroom and I enjoy every minute of it. I'm not wasting any space. I don't have marble tile, I have soft, non slip luxury vinyl plank. I have a regular, plain old shower instead of a custom tiled shower. We only have one child. We don't entertain. We don't have a million overnight guests. If I had build 3 bedrooms, I would have one completely empty room that would never get used for anything except maybe some boxes. I don't even have furniture for a third bedroom. But the resale value!!! Who cares? I am not selling. Instead I built a massively oversize bedroom for the one child. If he wants sleepovers, he'll have plenty of room for all of his friends without having to break out an air mattress in the living room. And he can keep all of his toys in his room. I hate toys in the living room. Everyone advised us on this kid friendly feature and that kid friendly feature. Uhm...he's only 3 for one year of his life. So no. I'm not going with a Mickey Mouse light fixture and miniature urinal, things that were recommended to us in all seriousness during our build. Moral of the story. Make your bathroom any damn size you want. It's your bathroom.

@nini804 -- thanks, that was my exact thought. It may not be a big deal for us but future buyers may want a bigger master. Since my original post, I've been playing around with the layout even further. Tried a few different layouts/arrangements while keeping the sq footage within 10-15 sf of the original drawing. Attached are 3 different variations (subtle differences) of what I am leaning towards -- again different from the original post. Would like to hear any thoughts/feedback... - First Picture: A couple of 3' openings (no doors) from bedroom to walk-in-closet (WIC). With WIC opened up, all clothing/storage will be behind PAX or some sort of cabinet / doors. NOTE: a variation of this plan could be provide sliding doors for the openings (instead of no-door) and this way all of the cabinets do not have to be covered with PAX/cabinetry. Still exploring my options. - Second Picture: Almost identical as the first picture -- except, WIC is opened up to the bedroom with no doors/wall. WIC & bedroom are separated with an island. This may be a bit dramatic -- making the master suite feel even bigger than it already is. It may also provide a great flow. With this option, ALL clothing/shelving will have to have PAX/cabinetry on it. - Third Picture: Bathroom door is from the bedroom, instead of the closet. ^^ This allows me to gain 3' of extra closet space. I am showing an entry door to the closet but similar to First/Second picture, I may have a couple of openings or no door/wall and just open up the entire area to the bedroom. Thoughts / feedback?