If you throw down $150 for a first party made controller you should expect it to work flawlessly. More than a few people have found the opposite and, very reasonably, they're unhappy about it.
The first wave that came out couldn't even stay on store shelves over night. Everyone flocked to an Elite Controller once they found one in stock. Hell, even I couldn't wait to grab one.
To be honest, I LOVE my Elite Controller. I haven't had a single issue with it since I bought it around 2-3 months ago. The slightest thing I've noticed is actually in Overwatch. When the character selection screen comes up the slightest nudge will send my cursor screaming to the right over all choices but a simple press of the D-pad will stop it. That's hardly the issue others are having.
Many are reporting problems with the sticks being loose or wandering during games. In Halo 5 people are reporting drifting crosshairs that never cease. Some even point out that their left and right bumpers pop out for no reason whatsoever.
In Microsoft's defense they are offering a 90 day warranty with each purchase but that hasn't stopped someone from taking their initial announcement trailer and doing some work of their own to it. It's worth a pretty good laugh.