If you combined your sensor and target display, you would already have a detailed enough view to explain how this is possible. When you target a ship, you can see their orientation relative to you at all times. You also know their position relative to you. It's not far fetched to believe that those two systems can be expanded on in a dedicated gunner station to provide a detailed and lifelike view for your crewman. All it has to do is replace the triangles and squares with the ship holograms and then add the textures and effects. Boom, now you have a holographic representation of the battle. Now, add an intuitive camera for your gunners and you get what FD have made for us.
I mean, if your ship can already give you everything except for the detailed textures and effects in three small holograms on your HUD, then surely it can do the rest in a station dedicated to it. I'm always trying to protect my immersion, so believe me when I say I have given it a lot of thought.
These overlays could also just add functionality to the current view that we have. The lore problem with the "have the guy looking at consoles in his chair" thing is that to the crewman CMDR sitting in his own chair in his own spaceship and who has telepresenced onto the ship on which he is a gunner, there is no point to add an extra layer of simulation when he could just simulate being around the ship, using all of that sensing data, which projects for him a view of the ship and its surroundings. Having different view-overlays based on the different sensors would be a cool thing, and maybe someday we can get that, but having them on consoles that the telepresent hologram interacts with, and then piping that interaction to the CMDR himself, who isn't physically present on the other ship, doesn't make a lot of sense.
Holographic telepresence is an established fact of the lore, so adding additional steps to make it more immersive for you, the player, in a way that would literally be less immersive for you, the in game avatar, seems really backwards. The present implementation maintains consistency with the lore and setting without making compromises to either gameplay
or Elite canon, whereas what you're asking for would require us to suspend disbelief and imagine that it makes more sense to telepresently holoproject into another ship and then interact with virtually rendered screens, rather than just project that data.
Put another way, if today, right now in 2017, we had the technology for perfectly real, realer than life VR, and you wanted to play Elite: Dangerous, would you rather put on a VR helmet and project yourself to your computer where you boot up playing Elite via mouse and keyboard, or would you instead just project that you were in the spaceship?
In 3303, CMDRs use holographic VR to teleproject into a friend's ship, and man different stations on that ship. The ship bridge is the "social element," but when it's time to shoot things, they aren't gonna want to mess around with holographic screens and such like, that's insane. They'd just want to have the holographic overlay that best suits their needs. That's what we have here.
Slightly off-topic:
Also, the "don't like it, don't use it" crowd are asking people who hate 3rd person to simply give up their views AND go without an entire feature. That's just disrespectful and selfish. I'll never defend the person who says we can't have 3rd person because they hate it, but there's no reason we can't ask for both.
The "don't like it, don't use it" crowd are, many of us, afraid because the very last major named update was delayed for a long time because people demanded that things be rewritten to add an egg-timer because they don't understand the Elite setting very well. A lot of us are very excited to play Multicrew with friends (the Diamond Frogs have processed in over 50 returning players who are getting ready for multicrew to date) and we don't want to see indefinite delays because some people don't like 3rd person.
If Frontier finds a way to add other views and things like that without having to stop development on other features, that's great, but delaying things they have been working on for months in order to appease people who don't understand the setting of the game they're playing just isn't cool.