There are certainly alot of aluminum alloys out there that are far stronger than steel, and given that it about 1/3 the weight....
Only think I see being an issue is cost.
Manufactures have been using lots of cast aluminum for years. Blocks, heads, trans and t-cases, some rear axles in fwd cars, etc. I dont think corrosion issues is anything new, but certainly an issue. It is alot harder ro remove a bolt from a transmission casting or t-case on a 20 year old vehicle than it is to remove one from a cast iron engine block.