Sorry for filing such a kitchen sink issue...
Some comments on the current UI:
play action, but why isn't that action simply inside the right side action bar? At best, you could still align the editor with the paragraphs and just outdent the action, just like paragraph twisties are outdented.

cc @lszomoru @bpasero @misolori
I agree re: whitespace, it's come up in other issues too.
@rebornix do you know which editor setting messes up the editor padding? Even with "editor.glyphMargin": false it's correct for me.
editor.scrollBeyondLastLine controls scrolling past the end of the notebook
Sorry I'm not sure what screen cheese you're talking about in the second image
We're being too generous in using padding in this view. There is sooooo much whitespace for so little information.
We keep seeing this come up and it's for a couple of different reasons:
8px of top/bottom padding for when the cell is selected/hovered32px toolbar for adding new cellsSo that means that between each cell we have 48px of padding. I think the biggest gain here is to iterate on the new cell toolbar and see if there are ways to reduce that. I'll also tweak the margins on the others where I can.
Indentation looks broken: text editors should be left aligned with paragraphs. I see that we're making space for that play action, but why isn't that action simply inside the right side action bar? At best, you could still align the editor with the paragraphs and just outdent the action, just like paragraph twisties are outdented.
In the previous iterations we had issues with code and text cells being part of the same vertical path and having a hard time telling the difference between them. So in this iteration we decided to indent them to improve the visual hierarchy. We could tweak the margins so that it isn't so large but still keep the indentation.
Selecting a row makes it appear like it popped out of the screen with the eerie shadow
We've gotten mixed reactions to this, some love it and others hate it. You can turn it off by setting "notebook.focusedCellShadow": "#0000".
Why does every cell have a status bar? This takes up so much expensive vertical space and even creates screen cheese (see below). Why not put those actions inside the action bar?
This is an essential part of notebooks to determine how long a cell took to run, the results, errors, and other useful meta data. I agree that this feels a bit much when you haven't ran any cells and I wold like to see us hide this by default and then have it appear when you run a cell. Also, the language picker is only really meaningful until you have multiple languages, so I wonder if we could hide this unless we detect more than once language? @rebornix @roblourens thoughts here?
Pushing some updates to address the large amounts of whitespace:

Showed this during standup and the team said 馃憦 how 馃憦 low 馃憦 can 馃憦 you 馃憦 go 馃憦 so I trimmed it some more:

editor.scrollBeyondLastLine controls scrolling past the end of the notebook
Again, I really don't think this makes any sense in this editor paradigm. I don't feel like I'm scrolling around the viewport of a document model: I feel like I'm scrolling an actual document, so going past its end resonates really badly in my brain. 馃 Kind of like scrolling past the last page of a Word document. Or scrolling beyond the end of a web page.
Why does every cell have a status bar? This takes up so much expensive vertical space and even creates screen cheese (see below). Why not put those actions inside the action bar?
This is an essential part of notebooks to determine how long a cell took to run, the results, errors, and other useful meta data.
OK, let's say we need a status bar, no argument there. But let's style it differently. Why does it have to feel like it's a part of the editor? The cheese is the _floating_ horizontal scrollbar, in the animated GIF: it's just there floating around, not docked to any edge. Simply coloring the background of the status bar would do wonders. Even a top border.
I agree that this feels a bit much when you haven't ran any cells and I wold like to see us hide this by default and then have it appear when you run a cell.Also, the language picker is only really meaningful until you have multiple languages, so I wonder if we could hide this unless we detect more than once language? @rebornix @roblourens thoughts here?
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Between each cell there is a 32px toolbar for adding new cells
This is clearly something we should push down to under 10px. All we really need here is a 1px horizontal line and a floating action bar, appearing on hover, to the left where the left-padding is.
In the previous iterations we had issues with code and text cells being part of the same vertical path and having a hard time telling the difference between them. So in this iteration we decided to indent them to improve the visual hierarchy. We could tweak the margins so that it isn't so large but still keep the indentation.
I thought they already look so different, given the editor border and font change?
Showed this during standup and the team said
馃憦 how 馃憦 low 馃憦 can 馃憦 you 馃憦 go 馃憦so I trimmed it some more:
馃敟, though with the decreased padding, the focus decoration (top and bottom border & shadow) looks even more dramatic. I'd really love to see a non-3D approach here.
Regarding scrolling past the last line, personally I like it, and it matches other notebooks, but it probably makes sense to add a separate setting for it.
There still is no text indentation inside the editors #99363
Already fixed in master and the root cause is "editor.folding": false ;(
There is an entire page of whitespace if I scroll all the way down. This makes no sense in a non-text editor view. It feels very weird.
We can add a new settings for it. The purposes of supporting this are
I believe we've addressed most of these issues, below is a comparison from May's release (from when you original postd this) vs July's upcoming release:

If there are additional issues feel free to create one for each one so we can better track them all 馃槃
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Showed this during standup and the team said
馃憦 how 馃憦 low 馃憦 can 馃憦 you 馃憦 go 馃憦so I trimmed it some more: