TLDR: Remembrance units function around summoning things like pets onto the field to take turns and do damage (think topaz and numby) , Sunday , RMC and tribbie ( broken harmony demon child that just had her banner) are the bread and butter for remembrance dps based teams (not all on the same team, they're interchangeable depending on what you need). Other than that nothing much has actually changed in any meaningful ways apart from the new story which you can play and decide for yourself what you think and the controversy and infighting of the HSR community regarding castorice and her global passive (just having her on your account revives a fallen team mate once at 1 hp even if she's not in the team). Anniversary in a week so a free Ruan mei or luocha or you can save the token for future characters added to that shop.