I think the slowness mostly comes from the new modern UI they put on. Every video in a category is placed on a single, long, scrollable page and represented by a big piece of cover art.
This new age style of UI is better suited to a capacitive multi-touch display and not the older resistive touch screens of the eX2 era. Think smart phones pre-iPhone vs after.
I'm sure the older processor doesn't help things much either, though I think the A380 economy IFE is even slower then the 738's and A332's.
