The interesting thing in League of Legends is the existence of the "meta", which, for the purpose of this question, can be defined as the One Strategy That Rules Them All. The meta shifts between patches; but soon after a patch is released, a new variation of the meta emerges and everyone agrees that this particular strategy is, in most cases, objectively best.
It's not that Riot Games doesn't try to migitate this. For instance, they introduced Runes that were supposed to allow personal preferences to be a bigger factor in gameplay – that is, allow a bigger diversity of viable strategies. But most such attempts backfire: there soon emerges the One Correct Rune Page For A Champ anyway.
Oddly, I am told and I read on Internet, this is not the case in Dota 2. (I don't know; I don't play Dota.) According to information I was able to gather, in Dota "nothing is slated in stone" and many heroes can be legitimately played in many roles, there exist multiple viable lane distributions and multiple viable strategies.
This seems counter-intuitive because of another difference between the two games that is frequently pointed out – that is, Dota embraces the concept of hard counters (i.e. if you pick a wrong hero pre-game and are hardly able to be relevant in-game then tough luck, you should've picked another hero), while LoL considers such mechanics broken and instead strives to provide soft counters mostly. Superficially, hard counters would seem to make a game lean towards "slated in stone" strategy (the correct pick is entailed by previous own team and enemy team picks), while soft-counters would seem to allow more diverse strategies thanks to allowing a greater variation of champs to pick in any given situation.
Might I ask, what exactly makes a game have One Strategy To Rule Them All, and what exactly makes a game have multiple viable strategies instead? I provided the examples of LoL and Dota because I think the difference is most striking given the similarity between the two games, but I believe the question easily applies to almost any competitive multiplayer game.