Yah, arbitrarily asymmetric reward rates will just cause the network to provide an asymmetric peg. For example, let’s say we always reward buy side at 20% and sell side at 10%. Then the network stabilizes with 50 buy nbt and 25 sell nbt. We think we’re super clever for having a big buy wall now, but what happens when someone sells onto it? Well, the network must seek to keep the 2:1 ratio, so exactly the same switching issue arises, just with some arbitrarily awkward ratio pegged around. The end result is that instead of having a peg that is resistant to price moves in either direction we have a peg that resists price movement well one way but poorly the other direction. For an example of what that looks like, check out bitUSD.
The most efficient answer is to reward both sides in some logically consistent and symmetric manner and balance the network using higher tiers. If the network has too much sell side, we need to perform dilutions or institute park rates. Providing asymmetric peg rates only aesthetically solves the issue and does so in a woefully short lived manner.