I am interrested to hear on this subject. The first issue I saw when PSIM was being advertised was a lot of bells and whistles with no product to back it up. Basically it consisted of an extreme amount of consulting time. It also revolved around slick sales people who used to work for large vendors like IBM and SAP. Its all about building data connectors between systems. But the real failing points is that the customer does not have a good handle on their current business processes to be able to define well the objectives and requirements of the PSIM platform.
There's definitely a lot of customization requires for understanding, documenting and building in workflows. I am sure in some cases it is useful, but it is a lot like IBM / SAP style mega projects.
An interesting email from a member observed how there's risk to the integrator as well. The projects are long and complex. They can easily go over budget and create a client who is perpetually dissatisfied, turning the project into a money pit!
I have consulted to clients on whether a PSIM makes sense and I have led PSIM implementations. The four bullets you pose are valid and are more indicative, to me, of gaps in the procurement cycle and early implementation phase because they show that the customer is not getting, or hearing, what is and is not possible and what the long term investment costs will be.
PSIM deployments are complex - there is no way around that and a PSIM deployment won't solve every business problem. What they can do is unify disparate systems under a common interface and they can standardize on the workflow used in the monitoring center. The customer must become a partner with the PSIM manufacturer and their trusted advisor whether that be a dealer, integrator or consultant so that everyone has the same understanding of what functionality will exist through the PSIM and what benefits the PSIM will bring. I had a recent client who implemented a PSIM and it performed to their expectations, but another recent implementation that was frought with challenges where the PSIM manufacturer struggled with the inadequacies of the underlying systems software resulting in the client wondering if the PSIM was "worth it". In the long run - it will, but not without challenges. "Eyes wide open" is a way to approach these deployments so that everyone, especially the client, fully appreciates what can and cannot be accomplished in the PSIM.