sree though your comparison is very thought provoking.....i think both these director/producers have big flaws in thier story....
1) lack of respect for the institution of marraige......the heroes go through marraiges as if planning next vacation( abhi in astitva went through tree almost bordering on fourth, ekta heroes do the same).
2) protagonist are goody two shoes, self-sacrificing(even if it means getting love of your life married elsewhere) human beings with the roughest deal life can shell out. sometimes they have this holier that thou attitude and they interfere in everyone's life around them(often trying to do some good) and that puts me off.
3)the men in general are weak/helpless personalities that are lead by nose by dominant female in thier lives.(abhi, abhi's father in astitva.....mihir in kskbt). when they are strong they almost always turn destructive or end up having extramarital affair(simran's dad in astitva and gautam/karan in kskbt). the third category of guys bear everything quietly and work on keeping family intact(rohit in astiva ......sahil,his dad...etc in kskbt). it is almost as if these shows have no male character with balanced personality and the story is from a female perspective.
4)eventually all stories lose thier charm by these directors keep dragging them with the leaps. i would prefer a more cohesive story even if has fewer episodes and ends soon
while the stories bring up similar issues very often but still ajay sinha's show is different fare from ekta's when it comes to storyline.
ekta almost always concentrates on the family dynamics of a very rich joint business family with elders(who cling to traditionalism and may not reflect very educated thoughtline). strange though it may seem many families still insist that daughter-in-law wear sindoor and sari, touch feets on the elders, cover thier head and call things like pitaji, mataji, partake in some puja almost everyday...etc. those who have spend a part of thier lives in smaller cities of india will recognize this.while people based in metros and abroad may find it over the top , it is still a reality in majority of households in backwaters of india. so the culture and lifestyle of viranis may not be that off the mark as most of us assume(though you do see modernism blending at times). also family politics, marital rapes , forced marraiges etc are bitter , unpalatable truths though most of us may not encounter them in our lives.
on the other hand ajay sinha concentrates on a highly educated, middle class nuclear family with very modern and cosmopolitan outlook. since this the life most of us lead in india or abroad, we tend to identify with it. the women are stronger and modern and the problems too are those of comtemplatory world. we see no family politics(it is a very small family...there are no cousins and second cousins in the equation....almost everybody is related by blood so there is no division of loyality), no marital rapes or forced marraiges(everyone is educated and empowered and guys are taught to treat women with respect), no fight over money(no one is filthy rich and everyone earns to make thier living and thier jobs don't clash )and there are no clan/family wars(everyone is on thier own and thier is no clan enimity passed down over generations)