exRunner...

Your statement about the percentage change when riding in the big ring versus the small ring is an apples an oranges comparison.

If you are riding in the 53/21 and change to the 53/23 the percentage change in nechanical advantage or cadence is not affected by the chainring size - it's simply 21/23 = .91 or a 9% reduction. The 53s or whatever chainring size you put into the equation simply cancel out.

Also, if you compare the closest possible gear inches or gear ratios in the little ring to an equivalent in the big ring, the shifts when riding in the little ring can be smaller. As an example, the 39/17 is nearly identical to a 53/23. If you shift to the next smaller cog in both cases, you get a 9.5% (23/21) increase in the big ring and a much smaller change of 17/16 or 6.2% in the little ring. Of course this assumes that you have a 16T cog, which nearly all 10 speed cassettes do.