From a guy whose been using them pretty religiously, if they decide to have them decharge on a target switch, its going to be a big nerf and they are going to be completely useless against anything except buildings. Their damage is pitiful when its not on phase 3 and it takes about 7 seconds to get that full charge. 1 void ray cannot kill a carrier/bc 1v1 and if you invest in 2 just to kill 1, then you overpaid(that is if they decharge on target switch).
If they do decide to go back to what they were in alpha(complete decharge on target switch). Then they need to bring back a phase 2 damage and faster charge time. In a big skirmish, nothing last more than 7 seconds unless they're behind enemy fire or they arrived late for battle.
Fun fact: If you target switch or your target dies before reaching phase 2, you have to charge up completely again. So if it takes 3.5 seconds of focus fire to get to phase 2, and a target dies after 3 seconds, you need to start all over again, and can't just continue on another target to get that .5 second attack. Same from phase 2 to 3. That being said, I made a test map with 1 voidray + a field of speedlings. I was never able to get to phase 2.