In my application I previously created (with the Data Loading wizard) some proper working Data Load Pages.
That was in apex 4.1.1.
After our recent upgrade to apex 4.2.2, I ran into a couple of issues:
The previously created pages where broken (I forgot to take a snapshot with details, I think it was a mapping problem). Anyway, data was NOT loaded into my table anymore.
I re-created the tables with the wizard again (no major issue, I only hope I don't have to redo this every apex upgrade)
With the newly created pages:
Layout is bad (the Load train is on top of the page, not on the left). Manually I have to change the page template to e.g. One Level Tabs - Left sidebar
Repeated upload of a CSV file takes a cached copy in the database, it will NOT re-read the changed CSV-file. Restart the browser to force a new session (or I have to create some custom process to reset the Collections).