I just wanted to bring up the topic. Probably redundant in some way, but it's something I encountered in a moveset I had for gen V that is no longer valid in gen 6. With the change in nature power from being earthquake in wifi battles to tri-attack, it seems many pokemon, such as sawsbuck, will no longer be viable with nature power and might have to resort to natural gift for the same coverage instead. I don't exactly agree with this because of the fact that nature power, regardless of conditions, is now a special attack and only valid for special or mixed sweepers. As such, Natural gift, although useful, is not nearly as useful by comparison and will prove a large hurdle because of the one-time-use nature it has. Perhaps the only reason I bring this up is because it feels like a massive nerf that will affect the movesets of many pokemon that once found it a boon and prevented them from being otherwise walled.
On another topic, the base powers of many attacks have changed (for the better in my opinion) and will also severely affect moveset viability. Hidden power, although normally weak in general, took a 10 base power nerf, which seems quite significant because of its already low base power. It doesn't present as much threat as before and could prove a dead move because of missing certain # of hits to KO benchmarks against important pokemon that it normally covers. It's nice that it is fixed for players who don't care about their IV's.
On the other hand, some attacks got boosts that were much-needed. For example, crabhammer went from 90 to 100 base power, which is wonderful because of the accuracy drop from waterfall. On a pokemon such as adaptability crawdaunt, this turns out to be a 20 base power boost, which hasn't been multiplied by weather damage modifiers or weakness/resistance modifiers. Based on this, my guess about the new metagame is that many pokemon will be more balanced in terms of power while some may become extremely overpowered (crabhammer in the rain with adaptability = 300 base power without weakness/resistance/held item modifiers). Pokemon such as scizor gained an additional supereffective target with priority bullet punch with the new fairy type. Dragons got the needed nerf, although it is still deemed mandatory to have a fairy or steel type handy to absorb/nullify hugely overpowered moves such as draco meteor and outrage.
I guess I was just wondering when the 6th gen movesets will be opened up for older pokemon.