by Reb Gutman Locks
"You shall not ascend My Altar on steps, so that ערותך will not be uncovered upon it."[i] ערותך is commonly translated here as "your nakedness."
The commentators explain that this nakedness refers to the priests' bare legs which would be partially revealed under their robes if they would ascend the Altar by stairs. But ערותך has another meaning that seems more appropriate here. It also means "weakness", as when Yosef accused his brothers of going down into Egypt to spy out the "weakness of the land".
When we go up (ascend) using stairs we direct our energy pushing down onto the lower stair. In order to go up we must push down. When we go up a ramp we have to lean forward so we will not fall back. When we go down stairs our attention is on the stair below that we are trying to reach, so we will not fall down. When we go down a ramp we have to lean our heads back up the ramp so we do not fall down.
Whenever we do a mitzvah we do it with our strong side first showing that we are eager to do it. When appropriate, we do it with our right hand. Whenever we move away from a mitzvah we move away with our weaker side first, our left side, in order to show reluctance.
When we bring an offering to Hashem we want to lean up into the act, and not push down in order to go up. Our attention and effort should be going toward the mitzvah. When we descend from giving an offering we want to move away from the mitzvah "reluctantly", leaning back up towards the Altar, and not be focusing on the steps below.
"So that your weakness will not be revealed" seems to be a more appropriate understanding of ערותך לא תגלה than, part of the priests legs might be "seen" by stairs.
 Genesis 43:9
[i] Exodus 20:23