I'll tell you why, I haven't seen any explanation of the cause of the problems, changing a few bits and sticking the battery in a box might be OK on a Ford Fiesta, but not on an airliner, not for me anyhow.
Precisely.
Much earlier in the threads discussing this, images of Lithium-Ion batteries exploding were posted, drawing no comment. Those batteries were smaller than a house brick and looking at the image of the proposed solution, I'd be asking if the proposed box for the much larger aircraft battery is both fireproof and explosion proof, which are two entirely different things.
I'm certainly no expert on the design regulations, but while it may be acceptable to mitigate risk of fire by putting the source in a fireproof box (is it?), I'd say it's a quite different ballgame when you admit to an explosive risk and don't fix the basic design.
And I don't think Ford would get away with such a solution. But more to the point I don't think they'd risk such a solution, if only because the user would be able to see it each time he opened the bonnet. Whereas, Boeing are in danger of an "out of sight, out of mind" solution.