I would wager that 99% of users would fall into one of two categories:

1) The journal is completely adequate for their needs; or

2) No default configuration could ever be adequate for their needs, since they need to configure rsyslog to ship logs off the box.

I'm curious as to what sort of cost-benefit analysis would lead you to conclude that everybody in group (1) should be forced to install rsyslog as well so that the perhaps 1% of people who "need to monitor / alert on certain log entries in a legacy or upstream system that expects to open and watch a file" can be spared the horror of having to type "yum install rsyslog".