Moodle does have good test statistics: http://docs.moodle.org/22/en/Quiz_statistics_report
Moodle Workshop is maintained by David Mudrak, who is interested in discussions about how in can be made better. There is a whole forum for Workshop-specific dicussions, so probabaly best to start a thread there to discuss it. http://moodle.org/mod/forum/view.php?id=740
Information about how to upgrade your plugin between versions is in https://github.com/moodle/moodle/blob/master/question/type/upgrade.txt (and the same sort of things applies to other types of plugin too.)
A possible explanation for this: The first time cron is run in Moodle 2.3.x is quite slow, because it has to process all the quiz attempts that happened in the past. Once it has caught up, everthing will then work smoothly. (That is just a guess.)
This is a FAQ. The links to the reports are in the Navigation block. (This may well be a bug, but for now, just find the link.)
My guess would be that this question was made by copying and pasting from MS Word, and if you look at the HTML of the question, it is full of junk. If you clean up the HTML, it will work on all browsers.