You forgot the part that Roger (a Logia) most likely defeated WB (a Para) to become the King but this time (being non-cliche'), Luffy (the Para) defeats BB (the Logia) for the title of King.
Roger has been described as a "demon" when he fights. And everyone knows that darkness = demonic and vice-versa.Blackbeard join whitebeards crew to find the yami-yami fruit before Rogers death so I don't think Rogers fruit ( if he had one) was the yami-yami fruit Blackbeard would have known it
Oda also writes devil fruits to kinda match the persons personality
DO you understand what "cliche" means? Do you understand that if Roger had it, numerous amounts of poeple would be WELL AWARE of Roger having that fruit and make the remark that Luffy has the same fruit?I see what you are saying i really do but I think its gomu gomu fruit here is why.
We know that Luffy got the fruit by finding in a safe that shanks had next to him. Now its been confirmed when ever someone die there devil fruit reappears. Roger died and his devil fruit reappeared in the world, Later Shanks found it and as the smart and great man he is, He knew it was Roger's fruit and decided to keep it hidden and not let anyone eat it. He then come's to see Luffy who said he wanted to be a pirate king and then ate the fruit of the pirate kind.
Coincidence ? I think not, I truly believe in my theory and Oda as the great writer he is am sure he has set this whole thing up to show that Luffy is the only person to match Roger and the first thing that showed it was getting the Gomu Gomu fruit.