Here is MY thought on fly tying kits I have never bought a kit per se. I enrolled in tying classes and the instructor laid out all of the tools and materials we were going to use for his classes and bought them in the first class.
I think experienced fly tyers have to realize that the materials in fly tying kits are not the highest quality for an experienced fly tyer to tie with but to ME they are good enough for a new tyer to simply use as practice materials. So what if a deer hair patch is a little curled up around the edges, it still can be used. So what if the hackle is not from a $150 neck, it too can still be used. So what if tying kits have materials to tie certain fly patterns, they still can be used.
I'm also sure that an experienced fly tyer could tie some pretty darn good flies from the materials in the kits even with the lower quality materials.
Not all experienced fly tyers have had the opportunity to buy and try every kit that is on the market today and give a reasonable review of each and every one. The answer from the fly tying collective is always is "dont buy a kit"!
And yes, the tying tools in kits are probably not of the highest quality that an experienced fly tyer would use but they are probably workable for a new tyer. Some tools should probably be upgraded as soon as possible or when the tyers budget allows.
Some new tyers go whole hog and buy the best that their money can buy only to find out that fly tying for them is not what its all cracked up to be and simply lose interest. Sure they can sell their stuff on craigslist or ebay or a fly tying forum but it just may have been better for them to get a kit without shelling out hundreds of dollars for something to collect dust somewhere in a basement.
It is always good to hear the ideas and comments from experienced fly tyers but not all experienced fly tyers are experienced in all aspects of fly tying. I know I am certainly not and will admit it.
Enough of my rant and I hope its helpful. As always, thanks for looking