I dont agree. I started out with a TVM kit gun that required a decent amount of work. And while my first attemp wont win any awards, it taught me a lot about the building process. It turned out much better than I even thought. The OP has said hes put together a few kits. Having him get a Kibler,while a much better quality kit, will only perpetuate another easy to assemble rifle. Wheres the learning on that. Time for him to get his feet deeper into the mud.
While I don't entirely disagree, the "learning" in the Kibler would be what proper architecture actually is. I don't think one learns too much about proper architecture from CVA or Traditions kits. I do agree it's not going to teach much, if anything, about inletting parts or shaping.
Chambers kits (except for the Little Fella kit, which I'd never recommend for a 1st timer) are probably one of the better blends of starting with something that has the basics of good architecture there, but still requires some inletting, shaping, etc. In addition, you are pretty well assured of a quality lock (not that it doesn't take some work).
Track of the Wolf's kits can vary quite a bit in difficulty depending on which is chosen. They are good kits, but for best results, the builder should study the correct architecture for what they are buying so they know how to properly do the kit build. Also, I've found that many of the kits have L&R locks and triggers which take an immense amount of work to get to a well performing status. Once done, the L&R's are just fine, but I've spent a week just on the lock. This is another reason to try to get a kit without the lock inlet already there. Minimal limit to getting the lock you might really want.
Kibler, Chambers, and ToTW kits are the only ones I've built, so cannot comment on others. I will say, however, that if one wants to really choose how much challenge they want, don't overlook Knob Mountain Muzzleloading/David Keck. You can have them provide anything from a blank, to just the barrel channel and ramrod hole done to even more. You can get your barrel (if something you want is not what they have) and have it sent to them and inlet, etc. Probably one of the more flexible places to work with if you have any special desires as to what you want to do vs the kit provider.