I'm always rather stunned when I encounter Oracle "E-Business" suite, that anyone would ever agree to pay money for such an antiquated piece of junk. (Mind you that could be said of many products from many vendors).
It's just horrible, and based on the implementations I've encountered I'd be amazed if it didn't make just people's jobs much harder, with all the overly complex forms and the clunky user interface.
In my current line of work the HR and Finance systems have moved onto it and it's just as horrible as it was 10 years ago.
But I think there's a bigger problem really: I just don't think that this "one system to rule them all" approach is ever feasible. Time and again, large organisations from all sectors spend millions of <currency> running massive projects via the usual suspects which always run over-time and over-budget, and every time the promise is the same: One mega-system to run the whole business that is going to replace all systems that came before it and will also save the company millions.
You either take an off-the-shelf product and try to shoe-horn your existing business into the IT, which tends to fail badly; or, you buy an off-the-shelf product and spend years integrating and customising it, which then begs the question whether it would be better to pay for a bespoke product to be developed from scratch to meet the actual business needs.
Personally I think that is more productive to use a range of smaller software components across a business which are each good at the tasks they are designed for. Add in some linkage between bits where it's actually necessary, and probably a centralised SSO provider but otherwise keep it simple enough that individual components can be upgraded or replaced without having to throw out the whole thing and start again.