So here, a timber frame is definitely not cheaper, rather a bit more expensive than solid masonry. But it may be that no comparable thermal insulation for the garage and extension is chosen here, then that might be true.
A bungalow would be an option here, but in the initial post it says something about 2 stories. I don’t know whether that is a building requirement that must be met (which I assumed) or the wish of the builders. I could also very well imagine a bungalow here. For example, two rectangles pushed into each other as a floor plan, one rectangle the "public area," one the "private area," and between them you have wonderful space for a terrace protected on two sides by house walls. With small children, no fear of falling down stairs, barrier-free in old age. That’s something…
And between a city villa, a 1.5-story gable roof house, a pure bungalow, and Bauhaus (or whatever is meant by all that, I’m with 11ant there) there are still plenty of possibilities. THAT is exactly where creativity begins and a good and dedicated architect should then be itching to get started.
I would seriously consider making the ground floor area slightly larger than the upper floor. Then the desired city villa style with a pyramid roof could be realized upstairs, but downstairs there would be more space. That would be ONE possibility. There’s no basement planned here either, and I find the storage options overall quite limited.
Wardrobe: I stick to my view, there is too little space when 4 people come home together. Sure, you can store stuff under the stairs in a built-in cupboard, at least coats, hats, etc. But where do the shoes go? Say goodbye to the idea that everyone always and immediately puts their shoes nicely into the space under the stairs provided for them. Small tip: go into the hallway of a family with at least 2 children and preferably when they also have friends visiting. And you don’t even need children to completely throw the nicely planned order in your head out the window: I like to send my guy over; he still hasn’t mastered putting the shoes in their designated place… Where is space for a stroller (or two, if the children don’t have a big age gap)? The covered entrance area is at least useless in winter and in wet, cold weather. Who wants to put their baby in a completely cooled down or damp stroller? And just imagine four people rumbling into the hallway together (which supposedly happens in families), think about where they should stand alone so that they don’t get in each other’s way. The English manage queuing at the bus stop, but a lively family will not neatly line up and then one after the other nicely put their stuff in the cupboard under the stairs. NEVER EVER!
The kitchen is adequate but far from additional storage space. If I want to store everything in this kitchen (including drink crates, supplies, etc.), then I would find it too little space. I am a confessed fan of the often criticized pantry here, but overall I find the utility room in this design too far away from the action. Especially with children, you often need cleaning supplies quickly, i.e., vacuum cleaner, etc. Here you first have to walk into the extension. So I would provide storage space near the living/kitchen area. Whether that will then be used as a pantry or purely as a cleaning closet remains to be seen.