“ZipGrade doesn’t mark [wrong answers] on the answer sheet”
-It does actually. Zipgrade takes a picture of each test scans and adds an overlay to each picture. That new picture is then uploaded to the Zipgrade account. From there, teachers can print/email the graded tests.
“I’m hoping another technology comes along and makes it more convenient,”
-Canvas/Google Classroom provides an online quizzing feature that is even easier to use. The Chromebooks have an app that can lock down the browser to prevent cheating.
“It takes way too long to bubble in my answers,”
-you can actually just mark the bubbles with an X and zipgrade will still read it.
“The Student ID thing [on ZipGrade’s answer sheets] that always gets crossed out is annoying,”
-Teachers can import class rosters into zipgrade and assign each student an ID. The ID field is automatically filled in whenever teachers print off these custom answer sheets.

All of these points and more are covered in the tutorials that were sent out at the beginning of the rollout.