Steve,
Just out of curiosity, why isn't Fionn here to respond? It's not somehow related to the "Pull a Fionn" command on CMHQ chat, is it?
As for Israeli TCs, they only went to closed-hatch work when they got the Merkavas. If I remember correctly, among the requirements for the Merkava was very good under-armour visibility.
When I was in, our armour doctrine was mostly lifted straight from the Israelis, which was why our TCs would always fight open-hatch. It didn't improve their morale much to know that <bignum> percent of TC casualties were fatalities (though the percentage of casualties was roughly the same as for any other combat speciality.)
Wherever possible, I keep my TCs open-hatch. I try my utmost to keep infantry sufficiently busy that they don't have time to shoot at that nice big hunk of metal 100m away that's laying the smack down on them.
Much like bringing 1800s artillery right up just behind the infantry to give the others a little taste of amatol...