Show the timer for all the succeeding stacked pixels. Currently, you can only see the timer for the first pixel. I propose that the timer should be shown for all of the pixels in the stack, and not only the first.
A neat feature that r/place had was that you could click on a pixel and see the username of the account that placed it. I propose the same feature.
Consider creating a permanent canvas. It could be neat to see how a large, permanent canvas evolves over a long period of time.
If any of these suggestions require the modification of underlying code, and are not simple config changes, then I will suggest them upstream -- please let me know.
a decent number of pxls regulars use a userscript to track timer on pixels 2-6. im unsure if there was ever any consideration to add that as a native feature though as its inefficient to stack pixels anyways so the extra timer is only useful to tell you if the next pixel in the stack is sooner than a full cooldown.
When placing a pixel on your own pixel, the time delay should be the same as placing over a virgin background. I don't see the point in punishing a user for drawing over their own art.
Defenders should have a more favorable time delay than attackers. For example, when placing a pixel over someone else's pixel that replaced your previous pixel (defending), the time delay should be short (e.g. the same as when placing over a virgin background), whereas when you place a pixel over someone else's pixel that wasn't preivously the location of one of your own (attacking), you should get the longer time delay (e.g. 1 minute).
it might be unpopular opinion, but the 2x cooldown for replacing previous pixels shouldnt even exist. you get into odd situations where greifers have advantage when your piece uses virgin pixels. but you can also use this 'feature' to cause more problems as a griefer if you are smart about it. find virgin pixels in the art space and place on those so you keep low CD but the repair crew gets double CD.
and then you have the issue where if you want to update your art, you get double cooldown for the new piece cus you are going over pixels.
overall CD should be the same regardless of what or where you are placing, it levels the playing field for everyone. this is not really a great solution to getting the canvas filled out when it can be used maliciously and repairing gets nerfed for it