Question:is random battle/unrated random battle really random?
the thing is i see many pokemon repeated for example i see spirtomb a lot and if it was just as simple as a 1-710 roll then the chances of seeing that pokemon should not be as high as it actually is
so is it truely random or is some system in play?
Random battles aren't fully random, but they do make a random team of 6 using fully evolved Pokemon (you used to be able to get LC & NFE mons) & the movesets are selected from a pool of generally viable moves for the mon (some moves will be on the mon's set no matter what like King Shield Aegi). This makes the chances of getting a Pokemon around 1/400 so its probably just your luck making you see Spiritomb a lot.
A more random format is Challenge Cup, where teams, abilities, moves & held items are randomized as to what is legal on them. Another step further gives you Hackmons Cup, where anything, legal or illegal can happen.