It will clash with Akshay and Tiger’s Bade Miyan Chote Miyan. We know that the best Raju Hirani films (except Lage Raho Munna Bhai) are always released during Christmas but this clash is not a good idea. Hopefully either of the films will shift to a new date before then. Also, announcing the movie nearly two years before its release date leads to a lot of waiting among fans, which personally I think could be avoided.
Out of his 5 movies released so far, Lage Raho Munna Bhai & Sanju were non-Christmas releases, Sanju didn't released on Christmas due to SRK's Zero & Lage Raho Munna Bhai didn't release on Christmas due to Bhagam Bhag
But actually release dates are never a concern for him bcoz except Munna Bhai MBBS, all his movies were Blockbusters and content-wise, all his movies are Masterpieces, he has been the best director of Bollywood of this century so I am very much excited for Dunki also