Every generation we see a new mechanic introduced so as to obtain shiny Pokémon, or an overhaul to the shiny Pokémon system. In generation 3, we seen the system overhauled to no longer be based on IV's, but on other determinants instead. Those determinants were a calculation made by comparing the trainer's original ID, secret ID, and the Pokémon's personality. This generation didn't bring in much changes though, given that the rates remained the same (1/8192) despite altered data structures. Interestingly, it was the first time we seen trainers have pre-defined shiny Pokémon (Trainer Tower in FRLG).
In generation 4, they introduced the method of making shiny encounter rates better. Thanks to the PokéRadar, as we all know. After chaining the same Pokémon 40 times or more, we received a 1/200 chance of encountering a shiny Pokémon; which was the best rate to date. We also seen the introduction of the Masuda Method, which allowed us to multiply our chances to encounter one by 5 (1/1638). So generation 4 brought in a lot of interesting additions, but not many "changes" like in the previous generation.
In generation 5, we see the first instance of certain wild Pokémon not having a possibility to be shiny (Zekrom, Reshiram, Victini). But in this generation we see the Masuda Method having a better ratio for shiny Pokémon outcome (approximately 1/1638 to 1/1365). We also see the introduction of the Shiny Charm which effectively triples the chances of seeing a shiny Pokémon in the wild (if in the player's bag).
Finally, this generation we see the introduction of the Chain Fishing method and double the chance to encounter a shiny Pokémon in typical methods (1/4096). We also see the Friend Safari gaining a higher chance of finding a shiny. This, tied with the previous mechanics such as the Masuda Method, PokéRadar chaining, and the Shiny Charm; leads me to really hope they slow down on giving us new ways to hunt shinies. I would like to see alternative methods such as the PokéRadar, but not necessarily better chances. Right now, shiny Pokémon are becoming less of a "rare breed" and more of a collector's item that isn't even too hard to obtain any more. It takes the fun out of it, so I really hope that we don't see any further adjustments this generation. I think we might see a new method, there is that possibility. However I don't think they'll make it any easier for us.
