I've trimmed a Haindl----more than one, in fact---and as I look back on it, I wouldn't trim a deck again. For one thing, they're too hard to shuffle because, no matter how careful I was, I couldn't get the nice, even cut that new decks have.
I've recently learned how to shuffle bigger decks, for one thing, which is partly why I trimmed the Haindl. It was too big to shuffle the way I shuffle. I didn't like the key words, either.
For another, I just don't see any need to anymore. I know some people dont' like key words or the extra languages, like in LS decks, but you can learn to get past that if you just concentrate on the images in the deck more than on anything else.
As I look back on it, (for myself only, mind you) I think it was partly just an attempt to take a shortcut to being a "real" reader. That may sound funny, but that was it at the very bottom line, I think. Kind of like a little kid who doesn't get the hang of learning to play a game so he does other stuff with the game pieces and loses them instead?
I guess down deep I thought if I could just make them easy to shuffle or if I could just get rid of the words, THEN I could get on with reading the cards better. I'm basically lazy.
Now I've put in the work and time it took to really learn the cards and what they mean, so I don't have to do that stuff anymore. And if there's a deck I want to use that's too big, I finally gave in and decided to shuffle it in whatever way I can shuffle it instead of being stubborn and trying to just stick to the way I've always preferred to shuffle because it's easier that way.