This proposal is a major gameplay change, I'm not going to pretend it isn't. But I think it could be worth trying. I propose making it so that when you die, you just spec your teammates. The main reason is simple: under the current system, the team that died is rewarded with informational superiority, rather than the team that got a frag. I think it would also open up a lot more possibilities for surprise manuevers and sneak attacks if you couldn't ghost.
Example 1: Let's say I'm defending Cargo stations objs in a 2v2 and I die in the main hallway. I can tell my teammate whether the enemies are going vent or station 1, so he can make sure to get setup there to defend. If I couldn't ghost, the attackers could have the element of surprise, and so the remaining defender has to make a tactical guess of which station he thinks they will attack.
Example 2: If I'm a defender and I die at red codes room to an O HW who doesn't have the codes, currently I can fly around the entire map (holding mouse2 for super speed) looking for the carrier. If you couldn't ghost, the remaining defender would have to decide whether to (1)play near the center because he's unsure where the carrier is, (2)gamble and go all in on defending blue, guessing that the carrier will go there, or (3)guess that the carrier is going red too and storm the O HW. As an attacker, you could also try to fake out enemies, e.g. making it look like you're running a certain direction as you kill them, but then after he's dead you switch directions.
Example 3: If I'm an attacker and I get maxed in a room where some D HW is camping, I basically get wallhacks for the next 20 seconds because I can constantly inform my teammate exactly where the D HW is, so he can prefire him in the face right when he enters the room.
Example 4: During the transition from Cargo CC obj to codes obj, a defender can SK and fly through the entire map (holding mouse2 for super speed) looking for an OHW who is trying to hide at the next obj, checking every possible hiding spot.
Example 5: It's impossible to be mindtricked as a ghost. On Hoth, a jedi carrying the codes can mindtrick everybody alive on defense, but if someone on defense is ghosting, he can constantly tell his teammates where the MTing jedi is. I can tell my tech "Stand on the shield, he's far away"
I've been playing a lot of Rainbow Six Siege lately, and that game actually allows ghosting to a degree, but it's far more interesting than JKA siege. When you die, you have a choice: you can either spec your teammates, or you can look through the surveillance cameras(defense) or allied drones(offense). They can be destroyed by the other team, and a few champs can even place their own cameras using their unique ability. There is also a champ whose unique ability can make him appear invisible to cameras/drones. There's also an offense champ whose "ult" ability allows her teammates to look through defense cameras, so the defenders have to choose if they want to kill their own cameras to counter it. Basically, Rainbow Six allows ghosting, but is far more complex/interesting/engaging than just flying around the entire map at super speed like in JKA siege. It's a complex gameplay element, and you can get on the cameras/drones while you're alive too, so it's bigger than just simply "ghosting" while dead. Also, when your teammates are dead and your information on enemy positions is limited to a few cameras(which might be dead anyway), it really forces you to make tactical guesses about enemy positions, and it makes clutch plays by outnumbered defenders really exciting.
I do realize that our current system requires skill too, because it allows you to communicate a lot while dead, so people who are more skilled at communication can make a more significant impact. But I think the gameplay effects of NOT ghosting could be more interesting - at least worth trying out. Again, basically under the current system the team that died is rewarded with informational superiority, rather than the team that got a frag.
Also, it's worth noting that our current system is actually a major gameplay change from base JKA. When you're dead in base JKA, you are locked in place and can't move your camera, and you can't send teamchats to your allies that are still alive.