After the latest attacks on MIR, there have been polls to increase the required MIR deposit and the quorum, but none to increase the Threshold, which only requires 49.989% Yes votes for a proposal to pass.
I believe increasing the Threshold to 60% would be more effective in warding off attacks since the attackers had significant funds (millions of $) and might not be warded off by 1,000 MIR deposit or even a 5,000 MIR deposit. We do not know the background of these attackers to assume their only motives were to steal MIR and that they would be deterred by losing MIR.
In addition, by increasing the deposit amount and quorum, it becomes more risky for anyone to issue warnings on the poll page since it would now cost them 5,000 MIR, and with the increased quorum, they could lose their deposit. Thus an attacker could still attack MIR and force users to match their deposits with significant risks.
Thus I think it does make sense to increase the Quorum and Threshold, but not the required deposit.
Since all the scam attacks came from accounts only 2 months old or less, I think it would make more sense to require a minimum wallet age to make a proposal and also to put up additional collateral for any polls requiring a community spend at 20% of the requested community spend. If the poll is determined to be a scam, the deposit and the collateral are forfeited to the community pool.
While I understand these measures cannot be implemented now, I think they should be considered for V3 and view increasing the deposit as a temporary bandaid for the time being.