In my mind, the downed state has always been intended as a means of hope for a defeated player, a possibility of against the odds comeback. However, it seems it has become, instead, a means of trapping and excluding a player from a match. By only coming back in time to prevent a player from rising, a defeated player can be kept in down state for a very lengthy and very frustrating amount of time with no way to surrender or recover. I personally see this as a cheap method of match manipulation. No one should be forced to wait an arbitrary and additional idle or "near-idle" time in a match after already being defeated.
I would like to suggest a remedy: An abandoned down player should automatically recover more quickly. Abandonment could be measured in time since last damage or distance from enemy players. But, if a player is downed, and the attacker leaves, the player should have an opportunity to recover at an enhanced speed. Attacking players should be required to finish their kills.
Alternatively, there could be a rapid surrender button by which the player could choose to give up.