I think staking multiple pools, variable locking periods for security, etc. might be okay but I don't think they should be at the base layer. If we had even simple smart contracts like Bitcoin or perhaps even a tiny bit more powerful, then these sorts of features could be added as applications (and this is necessary for things like cross chain swaps, payment channels, etc.). That's obviously not going to happen in the next version but once we are done playing with SMTs, maybe we will start to realize that trying to satisfy every need at the base layer with hard forks needed for each and every change is impractical and foolish.