Currently the existential deposit for ZTG is 0.005 = $0.0032
The existential deposit for DOT is 1 = $5.42
To me it doesn't makes sense that we would allocate storage for $0.01 worth of one asset but not $5 worth of another. We should align the existential deposits so that the values are roughly equal
I propose we set the existential deposit of DOT to 0.001 DOT
I think it's not necessary to have an existential deposit (ED) of 1 DOT. The purpose of an ED is too avoid bloating the chain with dust accounts, i.e. accounts that have a low amount of funds and are not used anymore. Those just consume storage space.
For ZTG we determined the ED to be the amount of fee in ZTG that a balance transfer consumes, thus leading to automatic deletion of accounts that transfer "almost everything" to another account. In the case of DOT, this measurement is not given (yet), as transaction fees cannot be paid in DOT currently (except when receiving DOT from Polkadot). I think moving forward with an ED that similar to the dollar value of the ZTG ED is a sensible approach.
In any case, transferring DOT from Polkadot to Zeitgeist should not be possible using the UI in case the receiving account will be reaped immediately due to ED. For example, sending 0.99 DOT to a new account on Polkadot from Zeitgeist would lead to immediate reaping, consequently it should be permitted or at least clearly communicated in signalling fashion.