You are correct, those later SMS games are far better programmed examples, because SEGA developed them on Game Gear, which is largely the same hardware. Which is why the latter SMS games released in the 90s were light years better, especially the side scrollers. What it does prove out as usual is that if the console maker spends money to make good games, those games will begin to show "higher technical" capabilities and features, and make better use of the console's hardware.
I made that exact point earlier, but the OP wanted to know currently, were there any SMS games technically superior to some of the best NES games? That has led to us comparing the games as finished products. Back then you are correct, nobody knew about or cared about specs. The presumption was the newest hardware was the better hardware, which frequently was the case. However, when systems emerged about the same time, such as SMS/NES on the US market, or The Atari 5200 and Colecovision in 1982, there were clearly hardware differences. Differences which today are plain to see.
However, to answer the OP directly I think it is kind of impossible without getting the input of actual programmers from back then. Or at least someone who has programmed on both systems since, in homebrew. I feel the Game Gear ports were probably the height of what the SMS produced, because they clearly had the best budgets. Alianger has a different definition of technical prowess than I do, but that's part of the problem. What is "technical superiority?" We know that really didn't matter, because games that traded technical wowness for control, music, story, etc. were always more successful.