I know exactly the situations you are referring to.. and I have experienced them, however; this doesn't justify extending the re-hide time to insane levels or completely killing the role of camo in the game, if anything... Other solutions could be found, but the re-hide time shouldn't be too long.
After all, TDs and AT guns are meant to ambush and kill tanks.. so that's what they do! The counter is spotters.
I think it does. Revealing itself and expect to get "forgotten" by the enemie just a few seconds later is just silly. Shoot, reveal, relocate, try again. I counted roughly 15 seconds re-hide now, perhaps a bit more and i was fine with it.
Also how does it "killing the role of camo"? Once you found a spot and click ambush button it needs just 9 seconds to camo. If that would take 60 seconds, that would really destroy the camo system.
There is a huge difference between "going camo" and to go "re-camo" mid combat. What you want is a quick re-hide which is quite a nasty thing to see a tank that just fired for only such a short time that you have barely time to shoot back at it before it goes re-camo. We could just as well add a "perma-camo". That would surely not killing the role of camo, wouldnt it? This is a ww2 game, not a "Predator" movie.
Also spotters? funny, usually right in front of such guns are enemie spotters so that the guns can use their max range. So you end up all day long in a spotter vs spotter showdown trying to kill the enemie spotter before you can get to detect the enemie hidden units and to go finally into combat. Thats always truly exciting.
The role of spotters is to spot enemie units, the role of detecting units is left for reconassaince units such like bikes, jeeps and stuff alike.