What are people's thoughts on using SYSAUX as the tablespace for APEX, and why?
It's the default, and it's use is often referred to agnostically.
https://mikesmithers.wordpress.com/2015/05/25/upgrading-to-apex-5-on-oracle-xe-11g/
Sven recommends not to, but doesn't elaborate why
https://svenweller.wordpress.com/2017/02/01/how-to-upgrade-from-apex-5-0-to-5-1/
Gerald says don't put your data there, Tim suggested this extends to APEX metadata, yet Gerald doesn't immediately agree
https://geraldonit.com/2017/08/28/why-you-should-never-put-objects-into-the-system-or-sysaux-tablespace/
Joel inherently recommends it
https://joelkallman.blogspot.com/2017/05/apex-and-ords-up-and-running-in2-steps.html
And Tyler doesn't see a problem
Move APEX Installation from SYSAUX to New Tablespace
I seem to have mixed messages. Many APEX luminaries suggest not to, but the Oracle team don't seem concerned - any it remains the default.