RPM is not the only one

Unfortunately, neither is a drop-in replacement for Vixie cron. There's just too much history behind vixie cron to replace it with anything that doesn't support all the weird variations of crontab syntax. (Obviously, I'm talking about the general case, done on a distribution level. Individual sysadmins can do what they want, and that's fine.)

What should really happen is to develop a cron-like system with equivalent capabilities but a sane syntax, the ability to control things like "what happens when a jobbed is skipped" or "what if the previous invocation is still running", etc. etc. etc. Instead of reading crontabs, write a converter . It can fail on the corner cases so long as it tells you it's done so.