I want to announce that the slope blocks (see attachment) will be removed in the next update. The reason for this decision is the fact, that placement of this blocktype is really complicated, and there are also too many different corner elements required to make the slopes useful.
Please note that the ramp blocks are not affected by this change!
The next update will bring a new extended construction system, which allows you to place planks and other elements with precise positioning and rotation. This will be a great alternative to the slopes, so there is definitely no reason to mourn the removal of the slopes
It makes sense that you don't use the slopes anymore. All slopes that have already been placed in your world will be deleted with the next update, and the resources for those elements (stone) will be moved automatically into the player's inventory.