Honestly, this standard BCS dative+locative totally confuse my head everytime they use it. :/
I feel like I'll never get used to this.
Btw, this can never be restored unless the government took some entirely new approach to the language – taking some dialect which retained the old state and claiming it standard, official language.

You're talking about the singular declination ? I think that in some parts of central Serbia they still have the old locative singular but I don't know to what degree is it preserved. In modern standard there is some difference in the accent between the dative and the locative case but it's slowly fading away.

As for the old plural cases, they were pretty much preserved and alive in Vojvodina at the time of the language reform, the only thing missing was the final *h in the locative case because that voice had almost disappeared in that dialect. (So it would be like – Voziti se u koli' po cesta')  They are still used in some places of Vojvodina and that would be the great opportunity to prevent it's complete disappearance but I don't think our linguists will do anything about that. Those idiots are killing the infinitive in favour of *da + present construction ( Sad ću ti kazati – Sad ću da ti kažem)  just to be different from Croatians who have forbidden the *da + present construction.