I'm not sure what you are not buying… You have shown that you can bring back all matching search results (30,000!!!) and subsequently filter. My point is, over time, this would absolutely bloat out mds and Alfred as the sheer amount of memory needed to hold your 30k results, especially with OS X's caching. Imagine a user had half a million matching results, and a slower Mac with a slower drive and less memory.
From day one, I have made sure that Alfred is as lean and as unobtrusive to your Mac as possible, which is why I haven't implemented this bulldozer approach.