We last made drastic changes to smoke in update 6.12, prior to these changes when a ship was concealed in smoke regardless of its class it would hold its base proxy detect range. This led to a very heavy smoke meta which would see the biggest battleships hide in destroyer smoke and remain concealed.
We changed smoke significantly in that update to more-or-less how you see it now, which depending on the class of the ship and whether it has recently fired will determine at what range it can be seen. This significantly shifted the smoke camping meta which lead to a very stagnating gameplay style.
Now in regards to your concern, these ships that do sit in smoke such as certain cruisers typically have significant weaknesses to counter this strength, for example, the RN CLs have extremely fragile armoring which typically will lead to their quick destruction if not played carefully outside smoke.
Smoke for certain ships have different uses, for IT CAs and RN DDs it is very much defensively for re-positioning or for breaking contact, for other ships they do need to use it as an offensive consumable. Either way, ships are balanced with the purpose and use of their consumables considered.
We do not have any plans to change or address smoke at the moment as we are happy with it in its current state.
Fem,