At the risk of asking for too many settings or exceptions, personally I'd like to ability to NOT have the window title shown on single windows — it's more minimalist and allows the toolbar to be more compact.
To my mind this is overlaps somewhat with https://orionfeedback.org/d/757-dragging-tab-to-a-new-window-leaves-tab-bar-visible-with-only-one-tab/6
Where one wants/needs to see the current page title you could "simply" use your existing tab hover as Safari does.
I realise I can select "Hide Tab Bar" on a single window to get this behaivour, but that wasn't at all obvious, I only discovered it on a related feature suggestion here.
Thanks so much for all your awesome work on Orion — it's exciting to have a WebKit alternative focussed on efficiency. I hope momentum builds and you get more devs willing to contribute.