You're welcome to build something different, then.
Personally, I think 4.5ghz across two non-HT cores is probably about equal to an i3 for most tasks, and especially considering the price.
Unless you want to get a Skylake i3, which is pretty expensive at the moment, you're looking at a nearly a 200% increase in clock speeds over a 5th gen i3, less for a 4th gen in terms of clock speed, but price remains a real issue considering that even the 4th gen I3s are twice the price of the Pentium.
You're looking at compromises either way, but if our goal is to get a good budget processor for as little money as possible, and keeping in mind you'll upgrade eventually in the same socket, I feel like putting the bare minimum into the first processor allows you to save the excess for a better processor more quickly.