I think they are likely worthwhile now for many users, including many in uniformed patrol, but care must be taken in holster selection and protection of the optic. A hooded holster can already address many of the issues. The gun-bucket-with-a-strap holsters are probably no longer a good idea. I carry concealed now, both on and off duty, so I'd have to be a right mess to get mud under my suit jacket, although of course there could be some Lemony Snicketts Series of Unfortunate Events that lead to me having glass obscured by mud/blood/whatever is available. I'll still likely go to a dot for on duty carry once they are authorized.
I suppose you could incorporate some sort of offsets, although I don't know how that'd work with holsters and if it would be worth it.
I do like the idea of treatments on the glass. Fogging would likely be mitigated as well.