The way you wrote this makes it seem like swiping up instead of left or right is really horrible and confusing. Why? Previous versions of Android had a totally different lock screen design, so I honestly do not know why you feel so confident that the correct swiping direction should be left or right. Because Apple did it that way?
While it's useful having shortcuts to do these things, they've gone far too far and made it too hard to do what you most often want to do, which is simply unlock the phone. The old photo button worked well, for example.
They had also previously used "up" on the lock screen for voice commands/google now, so I for one have learnt never to use "up" unless I want to set a timer using voice (pretty much the only useful thing it can do).
Also, for what it's worth, I find swiping up to be easier to do one-handed on large phones.
As I said, swiping up actually feels easier to me on a large screen than swiping left or right. And putting notifications on the lock screen is a critical feature in my opinion, something Android has desperately needed out of the box for a while now. I use a custom lock screen just for that feature because it's so useful.
It's the swiping that I'm specifically disliking. Every time I swipe to the right it opens up the phone app. Probably there are many users who have formed a really strong habit of swiping a certain way to unlock their Android phone. I would bet on that direction being left-to-right.
Do you know if it's possible to change the way the lock screen handles swiping in some settings page somewhere?
Click the unlock button, swipe up on your phone, not left or right, pull down on your phone twice, click the settings button, ignore the randomly flashing menu items as you scroll down, find "language and input", click "Google Keyboard" (not "Current Keyboard"), click "Appearance and Layouts", click "Theme", click "Holo White".