First: make BGs a 2 team 3v3, with the lost team's spawn area closed off on each map. with 3 teams, all competitive value, even casual competitive value, is lost. you logically must conclude that a victory is due to both enemy teams targeting each other more than yours, and a loss is due to both enemy teams targeting your team more than each other. it has always been a negative aspect of BGs....

Second: make these key Battle Spirit changes:
-80% damage received.
-90% healing received.
-50% outgoing healing, additionally. (only affecting healing upon teammates, not the caster)

this is meant to slow things down while preventing endlessly healing through aggression. currently, even with 30k resists, you will easily die within a quick reaction break free animation. BGs have become so fast paced that it just feels like spawn, run in, cast 2 abilities, either you won or you died, repeat....

most notably, outgoing healing MUST be halved. currently whichever team has more healers wins hands down. by an unreasonably high margin. if ZoS can log how many healers per team each match a compare that to win rates, they would find teams with more healers win over 95% of the time, I guarantee it. healing should be a playstyle, not a deciding factor, and at half healing it would still be relevant as a playstyle I promise.

ZoS, you may not realize, but the BGs concept has the potential of becoming a multi billion dollar stand alone competitive take the world by storm sensation, so to see it mismanaged so negligently and erroneously is VERY frustrating. what I would do with the resources you throw away....

at any rate, these soft solutions should pick things back up. I would love to see it at least tested for a cycle.