Smokes, better flashes, flares, all of these things are needed and even then, inertia might still ruin PvP.
The reason inertia works so well in games like PUBG, is because the TTK is way longer, and the punishment for getting shot is alot less significant. Your life doesn't matter as much, your progression is not dependent on your survival.
The reason why people don't lean, or alt-lean, is because getting shot in the head is death. So people rapidly move to reduce the chance of getting shot in the head. It is a head, eyes game after all.
If people start getting tapped because the leaning in this game is so unbelievably slow and clunky, the game will devolve into a camp fest, and people on both sides will get bored/aggravated and leave.
BSG themselves have said it feels like shit. They didn't say that about the weight system when that was added, so that means whatever system they worked on, was bad enough that even they think its too un-fun to put in the game. That should say something.
Be careful what you wish for. I know i'm gonna get downvoted to shit, but i'm gonna bring this shit up if inertia ever gets added and people start complaining.