Interesting questions. What you're seeing could be a number of things:
1. Are your training sessions possibly too long? Have you tried doing shorter sessions, more often? Dogs, like people, have certain attention spans and only work optimally for certain periods of time. Rather than being "bored", the dog simply can't fully concentrate any longer, and may also in effect be exhausted from the training! The thing with clicker training is that it is a VERY mind-oriented game, since the DOG is making to get the click to work. Some of my guys have almost literally been worn out after a clicker session and slept for hours.
2. Perhaps the dog is getting bored. Are you sticking too long on one criteria before upping the ante? Some people think there is a fine line when doing criteria changes and asking for more. That is, if you stick too long to one criteria level your dog does too, and finds it hard to move on to the next level. That's why I liken clicker training to a dance between human and dog, on the human's part especially to know when to increase criteria and to try to make the transition as easy as possible, with little notice on the dog's part.
3. Is your reward not exciting enough, or are you always using the same reward time and time again? Perhaps you might use a combination of rewards in training - play, and different levels of treats. Use a lower treat for the so-so behaviours and use the high treats for super big steps done on part of the dog (aka the Jackpot). Or, what I have done is throw in a super-tasty treat for a "normal" performance just to keep the dog's excitement up! If you never know WHAT you're going to get, you're going to try a lot harder, and for longer, then if you know it's the same ole kibble time and time again! What things does a Swissy like to do in general? Any favorite toys they die for, chase games, tug? Something you can throw in for a bit of "oomph" during a session?
4. Are you increasing criteria correctly? When you are withholding reinforcement and asking for more, are you going from step A to B, or are you trying to jump from step A to E? Did you break your criteria down as much as possible to set him up for success, are you asking for too much? Is it possible to break it down any more? What is it you're working on now?
5. One thing a lot of people sometimes don't notice, and some people are surprised when they think hard on it, and that is - are what you are training, and what your dog THINKS you are training actually the same thing? For instance, is there something else in the environment that is being reinforced that you don't realize you are actually reinforcing? So that when you withhold reinforcement in anticipation of "your" next step, your dog, thinking you're reinforcing something else, does something else instead?
From what you said, one or a combination of these factors might be playing a role. But when it comes to a cross-over dog I do like to try to do the following:
1) Short training sessions. I don't tend to "work" more then 7-8 minutes at a time, usually 5 minutes sessions. (By "Work" I mean discrete training sessions....in my mind my dogs are learning all the time, and I am teaching them, but I still have "class" if you will, in which formal learning takes place).
2) Use a variety of rewards.
3) Make the criteria as small and concrete as possible so that you can advance very easily and your dog doesn't have to do a lot of guess-work at first. As he becomes more clicker-savvy you can slowly begin asking for more, but until he learns how to think for himself even a little bit, you can't ask him to do it in a big way.
4) Most of all, have patience. Try to put yourself in the training position of your dog. For ____ period of time he was trained with method A. He got accustomed to method A and that's how it was. Now you are implementing method B, which not only doesn't match method A, but in some ways totally contradicts method B. His reinforcement history with method A is making it very hard for him to excel at method B. But the more practice with method B he gets, the better he'll get at it. And as his guide you need to be patient with him while he grows in his new way.
Kim