As you might know the houses (Shacks) in liberty bay are kinda full of "overkill" items (especially the guildhall) in most servers. The houses are made by one person, the decoration is made by a player. If you want that house who says you wouldn't want to show your best items, even though the house is kinda old looking?
And who knows, maybe the fancy house was built recently whilst the market stalls are older and have been kept? I'm not the one to say how it is but I could imagine a few reasons to why the mixture is as it is. When you build a new house you don't build it next to another new house all the time. There are many places where an old house is demolished to make way for a new one whilst the surrounding houses are still old (reference: real life and courses in architectural history I've attended).
IMO you should mostly stay away from grass on roofs, though this kind of grass is something I haven't seen very often before (since I think this is a Venore sprite?) and could actually work (I at least think they look better than regular grass tufts on roofs).
Also, in the original Carlin the market stalls are made of a different combination of stone walls, old and new (patched, although without grass on the roofs), whilst the bigger building looks much newer.
But as you say, it's all about taste. I don't tell you to like the piece, I just point out a few thoughts on why it might be as it is.
On my vote, I am still undecided but have narrowed down my list. It's either #1 or #6.. I really wish #5 wouldn't have had those boat rudders as light hangers (by which the southern one has the lantern hanging in mid-air). Would've made my decision much easier (I really like the houses on the right, but by principles I do not vote on a rudder used as something else).