To respond to the last post - if one aircraft is level and another is passing through it's level then I hope that something other than vertical separation is being provided.
In theory, yes. But there are moments, when things go wrong. Let's say you have to stop the descent for some reason, or the crew stopped it. Which altimeter setting should they have? I presume that until they are at or above min stack level they should still use QNE, but do the crew remember that they should change altimeter setting just because they stopped the descent? And how do you descend another aircraft above in case a low QNH? I had a tough evening yesterday, so correct me if I'm wrong, but in this case the aircraft may be indicating 10000 altitude, but it is in fact at FL110. If crew is supposed to change to QNH at TL, then this problem is experienced only in proximity of TL. If crew changes it immediately after receiving descent instruction below min stack level, then you must remember about it all the time!
In my FIR there is fixed TA and broadcasted TL which always provides at least 1000ft of transition layer, so your system looks quite odd for me.
I can't think of any advantage of your system, while there do exist some problems that I pointed out above.