These are truly excellent posts. As you can see, it's well-appreciated by this audience.
This particular post highlights the difference in mindset between controllers and pilots.
While you could've issued an explicit speed instruction with the VAP clnc, it sounds like you figured the pilot would 'get it', and hence the restriction wouldn't be needed. The pilot, sticking to the letter of the law (ie. no speed restriction with the app clnc means he can go as fast/slow as he likes, save for any 200/250kts airspace-based restrictions), exercised his new-found freedom
Presumably, slightly better situational awareness on his part would've helped him realize that slowing drastically may not have been such a fantastic plan. That said, he may just figured that since there was no restriction, you really didn't care what speed he was at, and he couldn't hurt your sequencing.
I'm a (barely) instrument rated private pilot, and a pretend controller (vatsim). I can't tell you how beneficial it has been, to BOTH pursuits, to spend some time in the 'other' realm. The couple of hundred hours of flight time has made me a better pretend controller, and the few thousand hours of pretend controlling has made me a considerably more aware pilot.
Please, please, please, keep the posts coming, or as someone suggested, start a blog. You can't imagine how many ppl (particularly in the vatsim world) would be up for reading the stories from the airspace that you control. The blog wouldn't need to be deep and insightful...simply stories of what happened that day would provide many hours of learning and entertainment.