In the past, inconsistent swipe gestures were caused by bad touch sectors on the screen.
An easy way to test for this:
Enable
Developer Options (go to
About Phone in
Settings, then at the bottom, keep tapping on
Build Number and it will enable it)
Go back to
Settings and open up
Developer options
About halfway down, under
Input, turn on the toggle for
Pointer location
Now if you put your finger on the screen, you can trace it all over and it will show the path. If it jumps around, or stutters and skips a section, you likely have an issue with the digitizer. If not... you likely don't. Note that if you're using a screen protector and do have issues, you might want to try it without the screen protector as that could be a complicating factor (though it shouldn't if it's well-made).
(and don't forget to turn off that toggle unless you love the 'pointer trails' for your mouse on your pc!)
Do any of these issues warrant a device exchange?
A non-fully-functional digitizer, absolutely.
Games, most likely if you're having issues they simply haven't been optimized for 7.1, and that may take some time given how new it is and how few (essentially, 2) models are currently running it.
Outlook email, if it floods in emails... does it do that both when you're connected to wifi as well as only to the cell network? If only with one, could be an issue of connectivity. Also, you mentioned Outlook - 3rd party apps, again, may need some TLC to make them run smoothly on 7.1.
Voice detection? tough to say.