All good points

They'd also have to acquire OVER 51% of the entire supply in order to pull it off

As you say: extremely unlikely, especially considering that 2%-4% yields is too low to risk it just for that.
It seems like a very good solution for now but we need to keep tabs on how things evolve.
It's a better solution than Hive for sure, as yields on Hive are much higher and the timelock is shorter.
I look forward to seeing what Koinos devs can build with the smart contracts.
Pretty exciting stuff.