So on this note; yes the expansion rewards should be decreased now; to something like 10% and further it should also be vested so that the participants do not dump into the coin. (mentioned here: MIP.C2-0004: Option for re-staking rewards / Vested expansion rewards to reduce dumps - #3 by srisri2050)
Reducing the epoch interval I might not be a fan of but I think the alternative which is issuing fewer bonds is a better option. Reducing epoch time right now will cause the market to not be able to catch up with the protocol.
Further, the main problem here is that there are too many thinking participants that work against the interest of the protocol. These mainly include whales manipulating arth bond buyers and further arth bond buyers cashing out.
I believe the protocol should in some sense have better control of the market hence the suggestion #2.