How I wish yrkkh gen 3 had happened
First of all, let aarohi have been considerably younger to akshara, that would have butchered kaira's relation more. Making kartik move on after a year was the stupidest thing that the makers could have done.
Then, give Aarohi a more genuine reason to hate Akshara, make the accident with Sirat more Akshara's fault (cause what they showed was a really stupid reason really). That would have created some real need for friction, and the fact that aarohi would be much younger would be more relatable when she starts the hate to akshu. And Akshu's guilt and panic attacks could be more explainable. That would really give more realistic feel to both characters rather than making one mahaan and the other villain
Next, post leap, when they're doing the love triangle, wedding, all that, proceed it slow. Let Abhimanyu and Akshara face issues while DATING. Noone goes to marriage that fast. Or if marriage being fast was needed, go the traditional route, and make it arranged. Aarohi, since shes younger to akshara considerably, would still be in her studying phase so she cant really be that invested in trying to break up abhimanyu and akshu either. She'll just be a side character.
Give her more flaws then just hating akshara, like she spent so much time on her studies that she cant do the expected 'bahu' things like cooking or saree draping or pooja rituals, etc. That also gives the makers time to show Akshu in the birla house, adapting to them, learning to not interfere too much in the matters of birla house like abhi asked her, and forming bonds with them.
Show her having trouble adjusting to the hectic schedule of doctors, maybe show her missing her family terribly and falling ill and she is too hesitant to tell the birlas the reason, and her declining relation with aarohi as time passes. Show her trying to build a bridge with her sister even post marriage, by simple ways like sending home kachoris or calling her frequently.
Meanwhile, start neirohi in college. Could have made niel a bit more complex character, who was doing medicine in the hopes of being accepted by the birlas more. Keep them young and stupid, and introduce the whole anisha and kairav thing and then, after the kunal mehra leap, let that be for 2-3 yrs instead of just 1 year, and then bring in neirohi's secret relationship and abhira reunion. Also show aarohi secretly missing akshara in the 2-3 years and when akshu reenters her life, resentment that she left. Then the neirohi thing is revealed, and maybe show akshara supporting the two instead of trying to split them up, and show aarohi and akshara's patch up there. Aarohi could still do that birla hospital share thing, and niel could support her when it comes out, revealing he always felt like a second class citizen here and a fallout. Thats when manjiri reveals his actual parentage and neirohi shift out. Let them live independantly in a different house, and show their simple day to day struggles, and simple happinesses. Meanwhile, focus on abhira and maybe abhimanyu doesnt want kids and akshara wants them. So do a track on that, with akshara trying to convince abhi and finally after he agrees, the medical thing comes out. Then treatments and everything else keep it same until the whole niel dying track, but maybe put him in coma instead of killing him off, and akshara miscarries, and aarohi wasnt pregnant or anything. So post leap, everyone has lost hope that niel will live, and aarohi is the one who is adamant he's fine. noone dares tell her otherwise cause she gets panic atacks when someone talks abt him in past tense. Then, do the whole abhinav and akshara thing, and one tweek they can do is that abhimanyu and akshara arent divorced, she had an accident, lost her memory and abhinav saved her. Abhir knows abhinav isnt his dad, but akshara genuinely has no clue who abhir's father is. Then the kasauli track and abhimanyu and akshara meeting and manjiri still hates akshara and all that, and abhi can help akshu remember everything, and he slowly bonds with abhir, and abhinav can become good friends with the birlas who are grateful to him, and niel comes out of coma and eventually aarohi can become pregnant with ruhi and akshara with abhira and they could have ended gen 3 with a happy note that way and kill off akshara, abhimanyu and abhir in a car crash, leaving abhira orphaned, and then shown a leap to show exactly how abhir survived and his struggle in an orphange, and even niel and aarohi's struggle in raising a teen ruhi and how ruhi's bond with abhira is, and then they could have started gen 4. That way, ruhi and abhira falling for the same boy would have been more heartwrenching when it starts affecting their bond from childhood and blah blah.
I dont think anyone will read this, it got too long, but I really wish the makers had done this instead of ruining everyone's characters.