I had been away for a couple years only to return to this arrow key and horizontal text placement bug. I almost did a reinstall when I went into the prefs for the 10th time, and hit the reset all menus and warnings. I was able to keep working with all my old workspace settings.

Guys - This is MANDATORY to fix. How if I am able to move the right way with a pen/mouse I can't with the arrow nudge keys. Totally counterintuitive. PLEASE FIX URGENTLY

There is a native workaround to deal with it and a third-party automated solution.

To force Ai to rotate a coordinate system with the view, you have to go to Preferences > General and edit the Constrain Angle value. Put a negative angle in the field — so, if you rotated the view 37°, put minus 37°. When you do that, hitting arrow keys will result moving the artwork in a proper direction, and new shapes created will be drawn properly.

Unfortunately, the marquee you get when drag with selection tools will stay rotated — this is a separate issue.

An automated solution would be using DirectPrefs plugin from Astute Graphics. Open its preferences (in the panel’s menu and enable Show Constrain Lock option. This will add a small button on the panel. Once you press it, the plugin will automatically sync the rotation angle and the constrain angle.

Take a look at the screenshot.
The plugin is free, once you register.

Rotated artboard/canvas (view) shouldn't affect overall direction. When flipping 180 degrees, for example, clicking on the left cursor the object starts to move to the right and vice versa.

Elenit, yes, true, the team is aware of the disconnection you describe and it is under review.
To make most of tools work unrotated when the view is, you need to change Constrain Angle value to be a negative of you current view angle (e.g. minus 15 for 15). So far manually, but it’s going to be automated. If you can’t wait, you can use a similar option in DirectPrefs plugin form AstuteGraphics’ plugins pack — it matches the values for you in background.

AstuteGraphics plugin pack has a plugin called DirectPrefs, that has Constraint Lock option. Once enabled, it counter-matches the Constrain Angle set in general preferences, giving you the grid that is always orthogonal to a view, which makes arrow keys work orthogonal as well.

Sure it must work from the box.

I love the new option to rotate the artboard. It is especially useful when working on dielines with panels that are facing different directions.

Currently when using arrow keys for nudging an object, the directions remain relative to the unrotated artboard. Meaning if you rotate an artboard 180 degrees, the up arrow moves an object down on the screen and vice versa.

It would be useful to be able to set the arrow keys to work relative to the monitor and not the artboard. That way if it is necessary to turn the artboard 90 degrees, the left arrow would still move the object to the left relative to the monitor rather than moving that object "down".

I have the same request, I believe this is a major issue. Changing my entire working routines, shortcuts and tools -that I've used efficiently for years- in order to accommodate a new feature is not an option.
At the moment the feature works just for viewing. It's not helpful to work with as the controls are practically disconnected from the screen view. When using a rotated view, all the tools (nudge, align, zoom) should work as if the artwork is rotated too. Having the tools behave as if the rotation is 0° is not helpful at all, it's really time consuming, as it feels like a forced brain game every time.
I understand that those tools are tied with the document coordinates which probably can't be rotated, but there needs to be a workaround.

You can move the view with PageUp/PageDown and modifier keys: Ctrl to scroll horizontally instead of vertically, Alt to use smaller steps instead of large. These require two hands (unless you use the right one) though...

As for the view rotation... I’d propose to use Shift (I think it does nothing now but dings). Will it work for you?

Not sure if arrows keys should be modal for that, but that is my preference.

It can, but it still can’t do it automatically.
See, it is not the canvas that is rotating, but a 'camera' looking at it, a viewport. The axis is still at 0, and arrows work accordingly.

To do what you want, you should copy the angle of the view rotation, open Preferences: General and set the negative of the copied value to the Constrain Angle field. Turn on the grid to see if it 'straight' now.

I am considering this request as 'Allow Ai to counter-sync Constrain Angle with the rotation of the view' :)

Move view (<h> key) and rotate view (<shift><H> key) should also be operable with the arrow keys when one of these keys is pressed. This is how it works when moving objects.
This would be helpful for people with disabilities and users of graphics tablets, who can then place the keys on the graphics tablet keys.