People can still discuss the plot though, and I think it’s reasonable to complain. Besides, there’s a chance that the damn flashback will continue in the third season. The flashback is going nowhere, so I expect it.
Yes, I really understand the feeling of being annoyed because the flashback is too long. But there's no harm in stopping reading for a while rather than complaining repeatedly (which the author doesn't even read). I'm one of those people who wants this flashback to end as soon as possible, but instead of complaining, I'd rather save my energy by drop it for a while, and read again when Ian's back. I'm just giving advice tho, so that we don't look annoying.
This comes from someone who is also waiting for Ian: please don't comment things over and over again like "I miss Ian". I know how you feel but there are still people here who want to discuss the plot. I got information from Twitter that season 2 will end in less than 10 chapters (from raw chapter count) and it's possible that Ian will appear in season 3. So if you can't stand season 2, please stop reading it for a while!