You don't need to be a long-time reader of this blog to realize that I'm a big fan of being unconventional when I'm training. I'm constantly experimenting with exercises and seeing if I can find a new variation that does something for my training that I haven't gotten from previous exercises. I certainly don't discourage others from doing this either. This is how we collectively make progress.
I would appreciate it if people would realize when they come up with variations that aren't helpful to their goals. There are exercises that are very versatile and can be modified in a lot of different directions. Take the wonderfully multi-use push-up for example. You can turn it into a plyometric, strength-endurance, or max strength exercise. There are some exercises that aren't a veritable multi-tool of training though, and everyone needs to realize this.
Take the mountain climbers or the grasshoppers. They're good for strength-endurance and for explosive training. If you're a pretty strong person, as far as max-strength goes, you're not going to get much out of it for max-strength. So, it doesn't make much sense to try. So, when I saw that there's someone out doing them with T's, I just shake my head. To do these, you're going to have to slow down the exercise so your wrist doesn't collapse. By slowing down, you lose the value of the exercise. Besides, how much good strength training are you getting out of this exercise anyway?
Other times, modifications can be just down-right unsafe. One such example I heard of was a guy doing box jumps with a presumably-big rock in hand. Once again, we have another explosive strength exercise that I use and I like. I also love training with stones so no complaint there either. Combining the two, in my mind, isn't so good. What's so awesome about stone training is that it constantly challenges your grip strength, no matter how small your stone is. Doing something that requires fast, pounding action, like a box-jump, is a recipe to dislodge that stone... onto your foot!
Generally, exercises that have a strong, stable base to work from are good for modification from one strength attribute to the next. Go back to the push-up. You're working from your hands and feet. That's why you can modify it and go in so many directions. Ditto for the squat. Doing pull-ups is a little more tricky. Your entire bodyweight is hanging, unsupported, from your hands and wrists. Unless you're really strong and can do these in very high reps, you'll have to move slower and more deliberately. That makes it great for max strength and less suited to plyometric work (for most, anyway). T-handle work is the same way. Your only contact with the ground went from two hands and feet to two, tiny little pegs and your feet. Now, you have to move more carefully and add more muscle tension. Great for max strength but not so good for high-rep endurance work.
So, keep this in mind when you're experimenting.