Thank you for the feedback. I've been thinking about re-doing the perks screen for a while now as it's a mess under the hood so I'll consider some high contrast colors as per your suggestion. The placing should be more intuitive too.
Funnily enough, the warning prompt you suggested was a feature in the DD48 version, but it was removed because I thought it limited choice since some players might want to save their points for later or something. I should definitely add a sound of visual to indicate when unspent skill or perk points are available. That being said, you can always save and quit from the map screen and access the stats menu from the orb in the main hub if you failed to do so at the rest area.
Another feature it seems you sorta missed were the game speed controls, but that's on me. A button on screen to control that has been on my to do list for a while so for the time being the feature is only accessible by pressing Q/E in the keyboard. The tutorial for keyboard shortcuts is available at any time from the pause menu, but I guess it's not intuitive enough that the game can be paused outside of combat by pressing ESC or right click.