Chris Parker
Grandmaster
From a non-TKD perspective (although it does feature in my background), one of the reasons we don't spar is not that it doesn't allow certain techniques, more that it is geared towards strategies and tactics that are not desirable from an SD perspective. These include sparrings requirement to stay engaged rather than simply create an opening and escape. Honestly, it's more the strategies rather than the techniques, as many techniques can be used to express the same strategy, so by having rules to limit those, you're not doing as much damage to the application of the art, but by limiting the strategies and tactics, that's where you find real compromise to the effectiveness and strength of the art (from that perspective).