I asked a legitimate, specific, relevent, answerable question here...
It's legitimate and relevant, no argument there, and perhaps even interesting (at least to those of us with backgrounds in similar systems). But I really wouldn't call it specific or answerable.
You are essentially giving us two answers to chose from, and they are certainly specific enough, but... What we need you to be specific about is the actual problem you are trying to solve and not the ongoing debates in your company. You don't even mention what the disparate systems are about (in general terms at least).
A vague question will only bring you vague answers, and you have already noted yourself that the answer isn't really applicable to the specific situation you are facing:
Sounds impossible. Maybe when the world stood still it might be possible to wrap it all in code. In real: That won't succeed. You will have some parts more nice than others. Do you mean that large integrated enterprise systems such as Oracle, Siebel, Epicor, Peoplesoft, and thousands of others are "impossible" and dont actually, really exist?? Is that what you are saying???? Have you ever even written code for a large ERP system?? Do you know how they are designed and built???
I have written code for a large(ish) ERP system, and what I've realized is that ERP is a catch all term that roughly translates to "über complicated behemoth that's does what the client(s) want it to do, in a way that suits the client(s) and is different from every other über complicated behemoth that's does what the client(s) want it to do, in a way that suits the client(s) and is different from ...". It is important for us to (better) understand your current systems before giving you answers, because Stack Exchange sites are about giving solutions to practical problems, not about generally debating various positions. If a debate is what you are looking for, that's fine, but you are at the wrong place.
As a first step you should edit your question and give us a high level overview of the various systems and how they currently work together. I'd also remove the opening paragraph completely, buzzphrases like "very complex business processes" and "very dynamic environment" are completely meaningless. Give us technical details, not marketing-speak, replace some of the overly general fluff with concrete technical parameters and you'll get much better answers.
Lastly, closure is a temporary state and it's only meant to signal to you and to readers that the question is (somehow) problematic. And yours is, but it's not unsalvageable (or irrelevant, or illegitimate, or even uninteresting), it just needs a few clarifications on the technical side and we are good to go.