I seem to keep telling this to people, so I thought I'd make a public post so that people can mock me openly about this:
"What should I play in extended?" Is something that people often seem to ask.
There is virtually no point in giving an answer, unless it's for the ptq the coming weekend.
This is because extended oscillates to a much greater degree than other formats that are actually played. (possibly legacy is similar, but I wouldn't know).
In extended there's a large number of known archetypes. Plenty of which have quite linear lines of attack. As a result, the decks are very powerful, but CAN be easily hated.
Both the threats and answers are of a higher quality than standard.
Whether or not it is a good idea to play one of these decks depends on whether or not it's fashionable to run hate for that deck that weekend.
Current ext examples- Affinity, hypergenesis, burn, dredge are all decks you can beat IF you choose to be able to.
If one of these decks does particularly well one week, then it'll be hated more the next. Trying to stay ahead of the curve can help.
On the other hand, there are a lot powerful decks in extended, all capable of winning a ptq. So it's probably more important to play a deck you can actually play, rather than pick one up that might turn out to be the right choice, but you'll make mistakes with.
Winning at extended is more about knowing your overall gameplan than standard is. And this is made harder by the large number of decks that people can play.
I don't have a good way to end this, or much helpful advice, other than know your actual gameplan in every matchup and board out chalice against hive mind.