I dunno. Cron is particularly bad. Want a sane looking cron? You'll probably end up writing a wrapper script to handle stdout/err. Every time I deal with an annoying dev or proprietary binary, my crons turn to a total mess.
That's seriously, seriously easier said than done in about 10% of cases that this sort of thing comes up. Especially when dealing with awful vendor code.
What about an application that takes an arbitrary date as input? Keep in mind that we're talking about production-leven infrastructures with many potentially many thousands of servers that might have 10 different distros with many thousands of differences between each machine, so falling back to "Just install X" isn't a possibility.
Then again, there's something to be said for vetting an application/script for prod-use on its "cronability". I don't think that's the point you were going for, though.
Also: /home/on_a_phone/parse_today.sh `date +%Y%m%d`
Will fail catastrophically because cron treats '%' as a newline character for some silly reason. Have fun troubleshooting that one!
Side note - clean your damn leap second crons, Steve!