Season articles. Our main guidance for creating season information comes in the form of WP:TVUPCOMING and WP:TVOVERVIEW. We don't create a section in the LoE page until a sourced episode table can be created and we don't create a row in the series overview table until a section for the upcoming season has been created. From this it should be obvious that we wouldn't create an entire season article until such time as a sourced episode table can be created, although it is acceptable if substantial sourced information can be included in a season article for that season. Such information might include production or casting information specific to the season. Of course, none of the content should be based on assumptions. The first problem with Modern Family (season 10) is that all you really have is a date for the premiere, and that isn't enough to justify creation. If all we have is the renewal information and a premiere date, that is normally just added to the lead of the LoE page. The cast information that you have sourced from other seasons doesn't constitute "significant" information because it's not specifically about the new season. That being the case, the article should not exist at this time. Please remember, Wikipedia is not working to a deadline so articles don't, and shouldn't, be created months in advance just because you can. This issue has been addressed at length by the TV project over the years, including relatively recently. You should be able to find discussions in the talk page archives. (From AussieLegend).
