Wow, I like it, a lot!
What I like:
Front bed / Rear dinette. When one needs to be inside, usually due to weather, the best view is usually out the back of the trailer. Out the front is, almost always, the back end of your tow vehicle and the campground road. Putting the bed up front allows the "living room" (dinette) to be in the back where the view is likely to be better and a little more private.
Front bath. I also like the bathroom out of the middle of the trailer. The bath in the middle, for me, visually makes the trailer feel smaller. It forces the available floor space to be long and narrow.
Full size bed. Building a compact trailer always involves compromises on how much space to devote to what. For me, a queen size bed is overkill. Full size is plenty fine. At home, where we have 1600 sqft to work with, I like a queen size bed (and being able to walk around it). In a trailer, full size works fine (it is bigger than the bed in the 17'). As a bonus, in this layout, no more crawl over required in the middle of the night since the bed is north/south. It is an end crawl (like the 5.0), but, you don't have to climb stairs first. You have to compromise somewhere to get it all in.
No growth in the width. The trailer will still be compact, lightweight, and easy to tow and manuever.
What I hope for:
Windows! There is nothing like letting in lots of light to help make the space feel larger and less confining, expecially windows on all four walls. The 19' is pretty good that way, but, of necessity limited by the "big brown wall" down the left side.
A minor thing ... I would keep the fridge/microwave stack from the 19' and make that left side counter a little larger, like the one in the 5.0 (cabinets above and below), allowing another window in the middle of the left side.
An observation ... There appears to be a little space left over at the end of the bed. I am thinking that eases entry into the bed by leaving a little aisle between the bed and cabinet. Might want to consider giving that up by not stretching the body quite the full two feet and make a true 21'. Sometimes smaller is better. Back to those compromises ...
Great job! Looking forward to what comes next.
Bill