Jon Bois of SB Nation has advocated for that Broncos Kickoff idea in a video more than a year ago and I kind of like the concept... His idea (well, he took it from someone else and made a video) goes even some steps further, eliminating all KO and giving the teams a 4th and 15 at the start of each half, OT and after scores. Allowing a punt to get to a similar field position as most kickoffs or a real play to get the first down: youtube.com/watch?v=t_SsIKgwvz4
As someone who had to live through the introduction of the VAR (Video Assisted Referee) in European Foot... Soccer for the last years, I have serious doubts about the inctroduction to challenges on OPI and DPI situations. For every clear cut example (Rams-Saints) there are dozens of calls, where whoever fanbase doesn't get the call will get even more furious ("What about that "same" play 8 weeks ago...?").
It's (fairly) simple to decide on video if a player was out of bounds or if a ball hit the ground (and there are still endless discussions about the catch rule), but for all those real judgement calls...
"Was there unfair contact by player X or did both players instigate the contact?", "Was the throw catchable or out of reach anyway?", "Did the ball arrive at the moment of the tackle or was the defender fractions of a second to early?"
Who has the final say, the ref in the video booth or those on the fields? Why are you only allowed to challenge OPI/DPI, when a holding call / roughing the passer / false start etc can have huge impact on a game as well? And what if, after all those questions are answered, the Patriots happen to benefit from that rule change in a big game?