I'm not a fan of Priebus but I was OK when Trump selected him to his post because the 2016 election results were a win-win for conservatives in the U.S. -- a non-politician like Donald Trump in the White House, and GOP control of both Houses of Congress. Priebus and the RNC leadership deserve a ton of credit for that.
The item I cited above is the only reason to fire him, because that's the kind of thing he's supposed to be doing very well there in that role.
P.S. -- I don't think Trump is going to "fire" Priebus. More likely, there will be a shuffling of roles at the top and Priebus will land in another position.
[and Priebus will land in another position. ]
Unless he’s Chief of the WH Bathroom Attendants, I don’t want him in any position with classified info or daily contact w POTUS (unless it’s to hand him a towel and keep his toilet paper stocked).