It's not wrong, but I'm just curious about why you would want to do that. I've been thinking of doing the same thing with a certain deck, but using only the majors. I've never heard of anyone using only minors before.
It's not "wrong" but it is removing some of the forces of life out of the reading. The Big Lessons, the Karmic and Universal truths... they won't be there. If you're only looking to see the human and mundane side of things, I suppose it would make sense. You won't have those hefty Majors hitting you over the head.
I am curious on the reason as well. Is this forever to take them out or for a specific purpose?
I always wondered about this too. I went to a reader once who had me shuffle the major and minor cards separately. She did the main part of the reading with the minor cards only, and then she drew from the majors for more information, or to clarify something. I thought the reading was really good. She used the Thoth deck.
Nothing is really wrong. You develop whatever style works for you with the cards, and you develop it by experimenting with different ways of using them.
It does seem to me that if you take out the Majors entirely, you'll be missing out on some important aspects of your readings. Especially taking out the Majors.
You might want to try just reading with a deck of playing cards if you don't want to read with a whole Tarot deck.