I always disliked daily powers so a class like the slayer fighter really worked for me as getting all sorts of minor abilities and things that boost basic attacks was really cool. Now if you could just give it free access to fighter encounter powers it would be pretty sweet (that and change fighter encounter powers to essentially be the same but use basic attacks which probably be a good idea if they thought of it from the start but oh well).

The line would have been better received if it had come first. By the time this line came out a bunch of 4e fans had put a lot of value in AEDU (at will, encounter, daily, utility powers) design that when they started to experiment with going outside of it, such as by making two fighters with no daily powers, there were a bunch of people who decided this was going to be 4.5 (thus invalidating the older material) or a concession that they were "going to go back, to something done previously.

Personally I find them as the design team experimenting with new design ideas much like how in 3e you started to get things like warlocks, incarnum, ToM, and ToB.

One good thing about many of the classes released at that time and later is that they tend to have a higher optimization floor while also having a lower ceiling so they tend to be pretty good but you will not be making most of them into the most powerful stuff.