I find it telling that JWs do not accept secular reasoning on many topics. Or more specifcally there seems to be quite a bit of cherry picking for secular evidence that supports thier world view. This is the case with the means of Christ's death, the sign of the times, and the fall of Jerusalem specifically.
An organizations that may have no religious agenda can posit that Christ likely died on some type of a cross. However, these will be ignored as Christendom, apostate, and/or satanic reasoning since they are contrary to WTS dogma. Whatever. I'm sure the producers set out to disprove JWs categorically with thier program. I DVR'ed that same History Channel program since I found it fascinating.
There are some fairly exhaustive postings from a poster here on Jesus' death that you can probably find by searching here. His/her username escapes me at the time but he/she uses a avatar of some female singer.
Fun stuff.
BTW: I'm watching History Channel as I write here (and supposed to be working!) There is currently a program on about Armageddon. I guess some folks are getting worked up about the 2012 end times predictions. I'm sure this would give many a JW a mad-on for blood running in the street. Too bad they are not the only ones predicting the "End is Nigh!"
--Not Buying It