I hope in Gen 6 they do some dramatic overhauls. Let's break it down like this: They have the perfect chance right now to fix anything and everything they ever had a problem with in the Pokemon games. They are having a major overhaul in graphics that has never been seen before. They could really exploit this and basically make a new system. They changed up a lot of mechanics with Generation 3 and made it to where Gen I and Gen II couldn't connect. You could think of this as the 3rd wave of types of games where the next games would be compatible with X and Y but nothing before. What all could they fix? Well, in my opinion, they have a big chance here to do the following:
>New types (Fairy or whatever)
>Completely new movesets
>New type advantage chart to balance it some
>Give floating or flying Pokemon the ability by default as a property and let them have abilities alongside that
>Different implementation of weather
>New status conditions?
>New mechanics that take other kinds of stats into effect
>Fix evolution problems. For instance, get rid of evolutions that require to be in a specific location. Let Leafeon evolve with a leaf stone, dammit. No more trading with items... King's Rock evolves how many Pokemon? Right, not enough to warrent the existence of the item. Trade Porygon to get Porygon2? Trade him back for Porygon Z? Why do we have 15 different kinds of stones where some evolve like 1 line of Pokemon? Merge some of clean them up.

What are your thoughts on this? Not necessarily my ideas, but the idea of having a very big overhaul in this generation?
I understand a lot of these are done already in previous games and sometimes differ from different versions of the same generation. (Like Pokemon learning different moves in Crystal than Gold.)