Re: All this sounds very grand...
To be honest, people that choose workday (or any HRIS) know they are getting locked in, and won't want to change systems for a long time. At least with APIs and easy access to your data you may be able to have that data live in multiple places or easily export it.
I do hear you on the difficulty of keeping up with SAAS changes, especially when you have interconnected systems. But what other options are there? Monolith? DIY?