It is only an other tool for the box, the pro gun dog trainers that i know that occasionally use it, they use it with dogs brought to them for training that have a specific problem that normal ways aren't working so well. They would always train there own dogs in the normal way
I think it could be useful as u can reward very small movements pretty instantly, so if u can break wot ever ur training down into smaller parts and overcome it that way if its strugglin with it as a whole.
By the time u've finished saying good boy (and i know it only takes a sec or 2) the dog could be thinking or doing something else other than wot u were trying to reward so may confuse it wot u were wanting it to do (ie with early retrieve/bringsel training a dog could be thinking about spitting it out and by time u finish saying good boy could have spat it out and may think the rewards for thikling and then spitting it out)
I have no idea how relevant clicker training or a modified version would be for tracking training, but i would not dismiss it totally out off hand either. Jist because u have been training in a certain way for 100's of years no matter how good that system is, it dose not mean it cannot be improved or modified, do u not think there has been some changes/evolution in the way u train ur tracking dogs over the years. I'm sure that tracking shoes were a new fangled gadet when they first came out years ago and the old timers said they were a gimmick, much the same as a lot in this country did (or still do)
U could also argue in the uk we've been training gundogs for 100's of years yet in the last 30 years the way the majority are trained has changed dramatically from breaking to a more positive reward based system.
Unless ur pretty confident in wot ur doing with the training and ur dog i wouldn't vere? of the traditional path too much, it has been tested and proven for years althou if u encounter a problem it might be worth a shot if nothing else works