This seems like a longshot as I would of thought it would have been mentioned already as a big change. However, it definitely would sell some terrain pieces so who knows.
I don't think this is rumor is real, but the idea or concept is interesting, so it makes a good fathers day (for tomorrow) conversation.
From to AenarIT on Bolter and Chainsword
According to The Honest Wargamer stream/podcast (here, bookmarked: https://www.twitch.t...022?t=00h56m35s) there's a rumor going around that one piece of terrain (basically, a faction-specific fortification) will be effectively FREE in 9th ed lists.