You could always set the phone to never time-out. Failing that if the swipe bar is a bit fiddly you can use the Security settings to set an unlock pattern. Granted it's not much different from the normal swipe but I find that it's more responsive, plus you can set it so you can operate and draw the pattern with your thumb one handed.
Practice makes perfect though, I've gotten the hang of operating it one handed now so I can pull it out of my pocket and one-hand swipe it to answer the call. Besides i hear that the updates coming this year will include a setting to make it one-tap at the users discretion.
Also it's a touchscreen phone, smudges tend to happen so I give it a good clean from time to time.
