Trogdor, Jayce, what kind of nerf you're speaking about?
As for light cloak-the only one can be used for escape, it's maximum capacity was even buffed. Currently heavy bombers have 1 minute, after update - even LFs will be able to cloak for 100 seconds. But... here's a problem-any snub with cloak will be able to escape fight, when he'll start loosing-cloaking time is less than shield regenration time. While it wasn't big problem in bomber vs bomber fights - you will end up SNACing/SNACed anyway. Perhaps increasing charging time to 16-20 seconds will fix that.
Medium one- well, my cau8 Vidar have 2 minutes of cloaking time. And since you can't use heavier cloaks for escape, you won't sacrifice armor for additional time. Ambush means overpowering opponent(if we are not speaking about instaing snubs), you can't overpower same class without proper armor.
So, time compared to generic cau8 800 cargospace cruiser buffed, additional classes like Battlecruisers and Gunboats added. Gunboats still should sacrifice armor to mount it.
Heavy cloak will have 6,5 minutes in cloak, more than enough to fly 130k invisible.
The only ship class that will truly suffer from change-"surveillance" ships, which can be fixed by introducing special survey ship.