i was thinking of building a fighter archetype that exchanges bonus feats and maybe some weapon training in order to slowly receive all four sets of elemental bloodline powers, with the exception of 20th so sort of like gaining elditch heritage as a bonus feat but four sets of it, also want to change 20th level ability to reflect this janni inspired class, the question is this a good idea or would i just be wasting my free time?
I love making archetypes, even if people have issues with how I do them. If you love it, then do it! I also like your idea. It might be too much to give one class ALL of the elements, but you could at least make an archetype with a choice of one element. There is a 3.5 prestige class called Elemental Warrior (this version is already converted to PF rules) in the Planar Handbook that you could use as inspiration in combination with the elemental and genie bloodlines.