There is no need to make the new iPad Pros bullet proof. They just need to make it somewhat stronger. Internal reinforcement at strategic points can accomplish that, with or without a change in the materials.Yeah they probably will do 6GB RAM or (8GB for the anniversary edition.) Then again how many times has Apple just slipped by without adding RAM?
Again reinforced iPads will bend a bit less, but you still have a 12”-14” + long slab of super thin aluminum and glass, they will still have warping bend issues. My 6 never had a bend problem and the newer 6 and then 6S were not at all immune to bending. They just weren’t bent out of the box as much or from being in pockets. The other thing to take into account is that it’s a tiny device compared to one that is large enough than any amount of force on one side can bend it. I can’t think of Apple doing any kind of Magnesium or Steel iPad Pro, or something other than 7000 series aluminum (and 7000 aluminum isn’t like a 3x stronger material, it’s more rigid, but not invulnerable.)
BTW, I'm not sure where you get the 12-14" long aluminum spec, cuz the 12.9" iPad Pro is 11" long. The 11" iPad Pro is only 9.75" long.