Somehow I see this argument reduced to the equivalent of the Fellowship of the Ring using Eagles to fly straight to Mt. Doom. :-)
Yes, with the best explanation in both cases being that both the eagles and Joker are too much of a drama queen to do what must be done.
Not really no, but it's still a huge assumption considering normal Reapers can't spam dozens of lasers from their "mouth" either but Harbinger can. So assuming that he can't shoot backwards because his fellow Reapers can't might be jumping to premature conclusions.
Buttlazor technology has been deemed too costly for anyone other than Praetorians.
The combined species fleet is nothing more than a bullet sponge, fodder to literally throw in front of the Reapers to keep them from the Crucible. A distraction, at best. Nothing more, and it can't be anything more.
People need to learn that.
Sure it can. Conventional victory once the Reapers are here isn't impossible because we can't win a space battle. We can and we would've, if everyone hadn't been fighting over the idiot ball before they got here.
It would be more accurate to say
conventional defeat of the Reapers is impossible, given their independence in space and ability to just bomb everything to **** if things don't go their way.