Hm, I think when people think about new moves that will drastically change the metagame, we need to think simple. Just think about how simple moves like U-Turn and Stealth Rocks were and just how much they changed the game. The shiny new move that shakes up the metagame will be so simple it will blow our mind. Sooo let me bring up the topic of new hazards again.
While moves like 'electric spikes' and 'stealth fire' will change the meta, it does so by removing the niche of other pokemon. Let me propose something different: aggressive hazards.
I think this has been proposed before about entry hazards of different types, but instead of a long term presence stealth rock or the spikes have, aggressive hazards would be used for intense, short term pressure. For my example, I will use charcoals as a 'stealth fire' like move or icicles as a 'stealth ice' type of move.
These moves would do 25% on the switch in on the first turn after, 18% on the second, 12% the third, 6% the fourth, and 3% the fifth. The purpose of these moves would be to put pressure on the opponent and halt their momentum. This would allow the user to have a short window to move more freely. Sure, the oppenent could try to switch his Forretress or Ferrothorn on the first move after charcoals, but then they would be just sacking it from the 4x25%=100% damage. It would force them to wait, giving the user time to set up, bring out a choice user, clear the hazards on your side, etc.
Icicles would also be nice because it would buy you time from dragons that would want to set up on you or ground types that would want to counter your electric type.
The damage drop off per turn would be easy to explain as icicles 'melt' and charcoals 'cool off.' Also, stealth rocks and the spikes would still have their place for long term hazard damage. You wouldn't want to keep throwing your fire or ice type out to put up these hazards as it would be waste of a move. Aggressive hazards would exist to buy yourself a single opportunity.
I'm not sure if a move like this would be in the next game, however, I believe another move could be modified to fill this role. Future sight could be modified to 140 BP and hit the next turn instead. This would allow the user to get a turn to switch in or give an attack when the opponent needs to decide which pokemon he wants to take the hit. Again, I doubt something like this would happen in the game. However, I think the concept is worth thinking about.
I have another thought -- what about self-statusing moves; where you burn yourself as a drawback or something? For example, a base 140 physical fire move that burns you is pretty interesting - it'd be a physical dragon meteor, more or less. A Special move that burned you wouldn't need to be very powerful - a 100 base special flamethrower that burned you might actually see lots of play, as burning a special attacker protects it from other status... add in psycho-shift and similar moves/abilities, and self-status moves might just be obscene.