The emissions limits thus far are mainly intended to prevent puking raw fuel out the exhaust, which mainly comes from two sources: The scavenging losses inherent to 2-strokes, and the poor mixture control of the carbs which go rich enough to cause misfire with only a small increase in air velocity. On top of that there is an emission credit scheme, so not every saw must meet the same limits. It looks to me like addressing one of these main sources gets one pretty close, and there are many strato saws with conventional carbs.
The cooling kickup was always the best evidence that there was something to the claims of exhaust delayed scavenging, but the fact that they are putting fresh air strato systems on their high volume saws says it may not be enough across the product line. The purpose of delayed scavenging is simply to reduce the time that fuel is in the combustion chamber while the exhaust port is open, and I suspect that the exhaust delayed scavenging may create some delay, but shorter than that of a full fresh air strato system (this is indicated by the attached document which describes an attempt to model the transfer flow in a Husqvarna strato). It may be enough when combined with a feedback carb on some of their saws, given that the high volume units are now fresh air strato, often combined with a feedback carb. So you are correct that the effect is "subtle" - perhaps "minimal" would likely be a better term.
As for "all the crap required to make a fresh air stratified saw work" - a fresh air strato requires no moving parts. It is an elegant design. A separate air valve is not required, rather it is a performance enhancement that allows the strato function to be shut off at idle, and effectively gives variable intake port timing. Many newer Stihl and Husky saws use a carb with a split flow and single throttle plate (thanks to yet another Zenoah patent).
Last, a fresh air strato pulls cool air across the piston and down the transfers during intake, and then air and mix flows up the transfers as in a conventional engine. That is a much more appealing approach than pushing hot exhaust down the transfers. Also the gas that is used to delay the charge is going to be used in the next combustion, unlike exhaust which must be expelled.
