I think you just have early adopter buyer remorse. I get the same way when new things are a little different than expected.
So, with iPad Pro, it's basically the same weight as the first iPad, but, thinner and larger. Based on that first iPad (which I still have!) you learn to use it. Don't think it's appropriate to hang that thing out in the air. It's more comfortable to cozy up with than a laptop, but, it's not a pamphlet like the iPad Mini. You're going to want to prop it up on things, stick the corner into your lap, cradle it, tilt in your hand while resting it on a desk. Whatever works. Getting accustom to the size/weight and how best to physically hold it takes some time.
Usage is going to change a bit too. Reading? Honestly, if you're talking novels, the phone is so so so much better for this anyway. Newsprint column width text display by default and single hand use? It's perfect for reading. But if reading on iPad Pro is your plan, it's going to be a matter of learning the best way to hold and use the thing. If you're into iBooks, I recommend you use it in landscape 2 page mode with a relatively large font to keep from having way way too much text on screen at once. That will also make it much easier to use in bed because you won't have to hang it perilously near your face.
At the end of the day, though, the larger screen is the entire point. If it's not a benefit to you, then, maybe you chose the wrong device. If you're into drawing? You'll regret moving back down to the smaller iPad, you just need to realize the ideal way to use this larger iPad is different than smaller touchscreen devices. Work smart, not hard.