Please redirect this bug report to the Pocket Edition project. There's no Minecraft Pocket Edition option under Project selection when creating an issue
I'm unable to walk in a straight line with the current controls. Expanding the Directional Pad's size exaggerates the strafing. Shrinking the Directional Pad makes it more tolerable to move in a straight line however it's difficult to press on the Directional Pad accurately due to it's tiny size leading to accidental jump button presses.
MC:PE bug reporting has been suspended on the Mojira. Please report bugs related to MC:PE via Google+, Reddit, or the Minecraft Forums.