Sure, part of that is just that you tend to use it a lot when something's new and shiny. But no, based on personal experience I'm pretty sure the issue is in software - some subset of the new features enabled by iOS5 is taking more juice than was expected.
I did discover one such issue. I have the New York Times app and access to a subscription for it. After updating to iOS5, the first time I tried to use the NYT app, it moved itself into the new "Newsstand" and changed its behavior so I started getting "alerts" whenever anything allegedly newsworthy happened. I had never gotten such alerts before, because I had that feature turned off. It was ridiculously hard to find the option to entirely turn off unattended polling related to the NYT app because the setting isn't where you'd expect it to be. (It's in Settings:Store)
(Apple has apparently identified some of the issues and just started beta-testing an update that is alleged to fix them.)
I did discover one such issue. I have the New York Times app and access to a subscription for it. After updating to iOS5, the first time I tried to use the NYT app, it moved itself into the new "Newsstand" and changed its behavior so I started getting "alerts" whenever anything allegedly newsworthy happened. I had never gotten such alerts before, because I had that feature turned off. It was ridiculously hard to find the option to entirely turn off unattended polling related to the NYT app because the setting isn't where you'd expect it to be. (It's in Settings:Store)
(Apple has apparently identified some of the issues and just started beta-testing an update that is alleged to fix them.)