I really believe that Akainu and Dragon will have a showdown. If there really will be a final war at the end of one piece. I think that Luffy will have a final showdown with blackbeard (obviously) And that Dragon will go against Akainu.
Ill give a example of the situation. Luffy is one his way to face off blackbeard, Help his friends or to raftel etc. In the proces he gets stopped by Akainu. Later on Dragon swoops in and says he will fight Akainu and that luffy should keep going.
Since there are theories that Dragon is a former Admiral. (Which I believe.) It will be A former admiral vs former admiral showdown. Since Dragon once said something in dressrosa along the lines of: Seems like the White dragon has beaten the red dog or something like that. cant remember the page. And we see that Akainu holds a big grudge against Dragon. Probably because Dragon shamed the marine for leaving it and leading the revolutionary army.
Spoiler: What Devil fruit is Dragon using?
So the White Dragon vs The Red Dog would be a great showdown and I do believe it will happen. I wrote this article really fast so sorry if it seems sloppy and rushed. I just wanted to make my point. The reason for this is is because I wrote this huge ass article a time ago but can't find it anymore.
I would like to read your points as well.
I'm out. Peace.