For example, it's important to know at a glance which plugin between several is thoroughly tested, documented, and proven with 50,000 downloads and ratings, versus one that has been around for a couple weeks and only has 6 ratings. Know what I mean?

It would be handy to have an additional submenu item for "Search for page" or "Search".

This would allow a direct click to the search function (only), rather than click and load a page with the full list on it.

So saves on data for page, faster processor time, and would make for smoother user experience.

Thank you

It would be very useful if in the reading settings where these pages are assigned there was a a link to them pages for easier access.

It breaks the user flow and even though not many users see "small" user experience flaws like this as an actual problem, it does pile up until the point where users notice them and get annoyed by them. For me that point has come a long time ago, but I'm hearing people around me experiencing the same. "Why does this happen, it's stupid...", and I agree.
This made me submit this idea.

Notifications should be non-disruptive. Maybe slide in or pop on screen to get a little attention but it should float and not take up any active space. Floating it in an empty space in the admin bar would be ideal. For the sake of a quick explanation I've attached an example floating it somewhere else, but you can see it does not take up more space than it should.
Or success messages anyway... With messages that require the user to do something, that is different.

User case: When a user is working on a page and clicks the [update] button, the page reloads. This takes a second, depending on the speed of the internet connection and browser (and hardware), even on very fast computers and internet connections. During this loading of the page, many users already move their mouse to the position of their next action, whatever that may be. Whether it being clicking in the textarea, title bar, the [view page] button or doing a metabox action.
In any case, you need to re-adjust your mouse position after it has fully reloaded because of the system notification pushing the content down.

TL;DR
Float notifications in the WP Admin, make them non-disruptive.

Attachment: Visual explanation of problem/solution »

Additionally, plugin and theme developers could make use of this templating system as well for their plugins and themes.

1) Microsoft Paint, GIMP or Adobe Photoshop - their default colorpicker mode is better for average person. HLS - not good. In this case you should use what top corporations have used as default settings for great products. I know that HLS is more for designers but RGB is more for average human. Anyway, having an option to pick one of those modes would be the best (either by an user or by plugin/theme developer).

2) 8 color presets below picker - honestly, that doesn't make any sense. It's absolutely redundant.

3) Many WordPress modules need RGBA() version of a color. This is crucial. Alpha is often important.

4) Having input field show HEX or RGBA value of a color all the time = highly recommended. Why do users need 2+ clicks to access that if they can do that with 1 click? The correct way to do this is to have TEXT INPUT and inside that INPUT a square with the color (perhaps to the right). Currently you only have a square and no input field unless user clicks on a square.

5) Maybe no message "pick a color" at all? It is quite clear anyway.

6) Last but not least - currently WP3.5 colorpicker supports only position relative (shows picker below INPUT and alters height of the container structure) - how about a mode where picker has position absolute? It's again - Photoshop style.

7) API? Settings? Methods? Events? Where are they?

Well, to conclude: I would say that it's best to check how Photoshop's color picker works and copy that. It would be great to have all these improvements :)

As nice as it might be to paste it into the visual editor, I recognize that might be pretty tricky. It would still be cool even to even have a box in the media uploader that would allow me to paste an image and have WP save it into my media library.

When I use a smaller screen like my laptop, the title column gets shortened and the title wraps into a really tall narrow column, while the other less important columns are unnecessarily wide. This is frustrating and makes the list very difficult to read. The Title column looks this:

The ti
tle of
my next
post lo
oks lik
e this

Here is
the tit
le of t
he draf
t I wro
te afte
r that

Etc.

For this reason I wonder from the first day of using WP, that in the backend this functionality is hidden in a submenu under "Appearance". Who would expect it there?

I suggest to move the navigation entry "Menus" out of "Appearance" submenu and make an own toplevel navigation point for it. Maybe it should even be point #2, just following after "Dashboard"

I need to style this page for the client (they wanted a pop-up) but after an hour of googling it looks like the only option I have, other than hacking the core, is to add a feeble function which will let me add some styling and edit the copy that appears, a bit.