i believe the downstate system has both good and bad. The good, encourages teamwork, and also a second chance.
I noticed in released notes, that your dev team wanted to discourage zerging. That is good, because currently many players are pigeonholed into zerging; swarm together, or get swarmed. It takes an enormous amount of skill difference to overcome greater odds, much more so than other games. A good player in many other games can take on 2v1, or 3v1, regularly, if the skill difference is vast. Though still possible in GW2, it is much harder, because of the down state system.
finishing enemies is always highly dangerous, being exposed for those 3 seconds, even a downed player can down a player trying to finish them most of the cases. Add in a little help from a second enemy player, even a downed second enemy player, and the skillful player who had downed both of them, is suddenly down as well, and will more than likely not overcome.
this is a big reason why people zerg: you are not rewarded for attempting challenging feats like 2v1 3v1. You may down them, but that’s it. No reward.
There’s also little penalty. Elementalists are the biggest abusers of the downed state, particularly in WvW, (but also in spvp). With no cooldown on mist form, they recklessly go into crowds, then return to their zerg to be ressed. It is totally obnoxious, having to kill many elementalists 4 times before they’re really dead. Easy solution is to put a cooldown on the skill, or make it last less time, meaning eles can’t go very far out past their zerg as recklessly as they do now.
Finally the rally system. An obvoius problem is Rally in WvW on PvE mobs. One shouldn’t be able to rally in a pvp fight by killing a boar, or a skale… that is absurd. A solution would be to add a tag, if a player is attacked by anotehr player while fighting a pve mob, then it can no longer rally on the mob.
Rallying in general, from downed state. I also think it’s absurd an entire group can rally from slaying one enemy player. There should be a cap, and a small one on how many can rally. Maybe, if there are multiple people that can rally off a downed enemy, the one that got the last hit rallies, and only him. The others must find another, or get ressed. Again, this problem makes being outnumbered an even greater problem. For example, two skillful players battled 4 , and downed all of them, but one went down also. The 4 downed players kill the downed opponent, and suddenly it’s 4 v1. The 4 easily defeat the 1, who is still heavily injured. The 2 skillfull players got nothing. Again, this contributes to the problem of zerging.