More ways to get crates? Like gun levels, player stats (like every 20 kills or 5 wins you get a standard crate). Some random events that reward crates/random gun when won. More gambling options like a spin to win with a total jackpot. A counter for total crates opened, legendaries unboxed, purples unboxed, scrap spent etc.
As for the biased weapons from the same time as corrupts, maybe a gun with one high stat (50-150%) with all other stats having the range of -50% to -150%. For example a HUGE with 75% damage but -150% recoil and -50% mag size