Has the Gen 4 OU changed since its fall ?
What are the currents trends ?
If I remerber correctly DragMag and water/fire/grass core were a thing. Is it still true today ?
So when Salamence and Latias were banned, I remember everyone predicting the rise of Infernape. With two of it's main counters gone, sets like nasty plot mix ape were predicted to go crazy. Instead it was the rise of another popular fire type: Heatran. With the loss of Latias a lot of people had trouble checking threats that Latias easily covered and Heatran was very good at checking grass and electric types, which rose in popularity. Heatran rose to the number 1 used pokemon with a useage over 40%.
The main reason grass and electrics became more popular was because of the rise in water types, as latias was again naturally a great check to these. Also Latias checked grass types and to some extent electric types, so it was easier for them to be effective.
Water types have become very dominant in the tier, with the lack of dragons it's a very easy move to spam and is very easy to find coverage for (bolt-beam, dragon, normal, rock, flying, dark etc. all have good coverage with water attacks). This is part of the reason that Starmie is now the most used pokemon in the tier. With the rise of all three types, fire, water and grass, it's easy to see why FWG was considered a thing, although the core itself achieves nothing special.
The other reason for Starmies popularity is because the metagame has become very entry hazard based. With the loss of Latias and especially Salamence, offense took a huge knock back making it harder to break teams down. This makes passive damage such as entry hazards more useful. Entry hazards are also more commonly used on defensive teams and with less offense to worry about, defensive teams have become more popular. I think everyone would agree that Starmie is the best rapid spinner in the tier, which is very useful in the metagame. Another small note is that games are typically longer, so people switch around more, making the use of a rapid spinner more popular.
The rise in entry hazards has made Rotom forms more popular as they are undoubtedly the best rapid spin blockers in the game. The increase in both Rotom and Starmie has made Scarf tar (surprisingly) even more popular than it was in the Latias era.
One impact from the loss of Salamence is the change in the lead metagame. Salamence was such a huge threat offensively that you had to have stealth rocks up, otherwise it would repeatedly switch in and tear your team apart. This made suicide leads much more popular, where their sole purpose was to set up stealth rocks, they often carried taunt, to prevent the opponent from doing the same e.g. Azelf and Aerodactyl. The loss of mence also saw a decline in the use of anti-leads, a lead whose purpose was to prevent stealth rocks and have a good lead match-up e.g. Scarf Jirachi, Weavile, Infernape and (to some extent) Machamp. Nowadays people tend to lead with whichever member of their team has the best lead matchup (as can be seen by the rise in Zapdos leads), although dedicated leads are definitely still popular.
Drag Mag is still used and still effective. There's really only three dragons to choose from (Dragonite, Flygon and Kingdra). But they work well together and I personally still have some success with it. It is obviously no where near as popular as it was in the Latias and Salamence era.
The metagame has been stable for a while now and almost any style of team can be effective.
