Shouldn't they be some sort of stand-in and only take care of routine / bureaucratic tasks?
It's a system that is ripe for making these already out people do stuff that is ideological and hardline, while the voters obviously don't want it.
The long transition from FDR to Hoover caused the 20th Amendment to the U.S. Constitution to be passed and ratified which greatly shortened it -- it's still too long! One of the reasons the transition from general election to Presidential inauguration is so long is that the Electoral College has to convene, and that legal challenges to electoral results have to be resolved -- all that takes time, and some times (e.g., in 2000) it takes almost all the allotted time. Still, it could probably be made much shorter, but it would require yet another Amendment.
I suspect long transition periods in State governments have similar reasons for being.
Kelly voting with the majority is quite tame.
I remember that a ton of wonky stuff has happened in the "lame duck" period, but it does seem to be standard.