2. Could you create a waiting list for swaps that users could opt in for if they wanted? For example, there is no XMR left, but I opt in to be placed on a waiting list for x amount of hours. I deposit the coin I wish to swap for XMR and then I wait to see if the reserves will fill up? When they do, I get my XMR 2/6/12/x hours later if my turn comes.
This is wrong in many ways. Pre-selling something you don't own yet is always a bad idea.
It would oblige exch to keep user funds, an additional unnecessary security risk.
It would no longer be instant exchanges, functionally the same as other CEX, it is not what we users want. Funds somewhere without control, for an indefinite period
To manage the price, a significant up or down of the currency price can happen, so the customer will not receive the amount that was planned at the beginning of the swap process.
I assume that such a list would have to be public because you don't want to send Bitcoin without knowing that there are already 20 open orders pending. A public list on exchanges which prefer anonymity seems like an illogical solution.