Thank you for your detailed post. You have highlighted some issues that QlikView Expressor can indeed help you with. I would also emphasize that you may be able to address some of these problems by creating and using a QVD layer - this could help shield the QlikView applications from source system changes.
Another tool that would help you manage your current environment is the QlikView Governance Dashboard. You can download and use it for free to scan your current deployment and create a central point of management for those QlikView applications. You can download the Governance Dashboard here: http://market.qlik.com/qlikview-governance-dashboard.html
As for Expressor, some of the key benefits are::
- Semantic Metadata - allows you to conform heterogenous data sources into a common data model. This can be the model(s) already created within QlikView.
- Built-in source control - dataflows and other artifacts created within Expressor can be checked into a central repository and versioned over time
- Graphical designer for data access and provisioning - minimize the need to develop and maintain individual scripted solutions
- Logic re-use - reduce or eliminate the need for 1-off solutions by leveraging Expressor's Semantic Metadata layer
- QlikView Expressor Connector - ability to seamlessly call Expressor as a data source directly from within QlikView 11 without having to manually launch Expressor. QlikView load script(s) automatically get created. This makes integration into Publisher very seamless as well.
As for training, here's some courses you could consider:
Finally, I believe the Account Executive for your organization has a call setup with your company today. I've let him know that you're interested in how Expressor can help you manage your QlikView development, deployment, and environment.