One could argue that it is essential for development
I disagree.
1. Ok, it's a very easy statement to make considering it is the only reality we actually know. A man without nipples would look extremely strange in our reality but that doesn't argue that it is essential for men to have nipples - indeed I would typically suggest otherwise. It isn't in any way essential but it is a fact of existence.
From here we progress to question whether pain and prolonged suffering could really be considered 'essential'. Given the context of discussion we must do so from a god exists/religious understanding.
2. Your statement only reflects the very basics. I am unsure exactly how anencephaly could be considered 'essential for development'. Should you have ever got anencephaly, it simply wouldn't have been possible for you to have ever developed in any way whatsoever.
You instead seem to be thinking along the lines of cuts and bruises -
"ouch that hurt, best not crash my bike again", which certainly might aid our existence in
this fallen, chaotic, world of suffering but interestingly any 'loving' parent would remove that pain if they were able. It is only due to our inability that we have no choice but to put up with it.
Sometimes we cause suffering - for instance when we take our children to be inoculated. We cause them suffering, (not prolonged), in order to help them. The pain of the injection, the benefit of freedom from future disease. But as a 'loving' parent, we would remove that pain if we could - we have no choice but to allow that pain because it shields our loved ones from further and more serious pain, (prolonged suffering).
Is prolonged suffering 'essential'? I don't see the argument. I've never had prolonged suffering of any form and yet I seem to have somehow made it here without
needing to have gone through it. That's not to say that I wont in the future, but I don't see where you could possibly then assert that it is essential that it happen. Why would cancer be essential? What's it going to do for me other than kill me that an omnipotent entity couldn't have managed to bring about without it? If I got cancer and died, would that aid my development more than not getting cancer? How so?
If we delve further into your world of "essential development" we come up with some truly bizarre things. Strange as it might sound, some 30 or so people die every year from meteorite impact, (can't remember the source, sorry - and it could be inaccurate). Was that somehow essential for their development? Is it somehow essential for a rock to fall out of space and land on someones head? If it is not essential what are you saying? If not essential, are you claiming it is gratuitous? If so, do you not have a problem with gratuitous suffering?
3. We live in a fallen world. A world of anarchy and chaos. Was it essential that the fall happen? If we say yes we remove any blame from humanity and then can only say that a god has specifically designed us to suffer. This raises question of morality. If we say no, there goes any argument to it being essential.
If Adam and Eve had have just literally kept their mouths shut, we would be in a world without pain and suffering - which was cursed upon us due to their mistake. If they hadn't have eaten the fruit - we would be in a different world, one without pain and suffering - and not be claiming that a fallen world of suffering is essential.
4. What about predation? Would you assert that predation is essential? Does the fly somehow 'essentially develop' by having the spider eat it? What of the cow that has it's throat slit. Is that suffering somehow essential? Kindly explain.
5. Finally: You stated that
"one could argue that it is essential". Kindly do so. Telling me that parents don't spoil their child, (many do - in fact one of my best friends was incredibly spoiled but has turned out quite alright), isn't an argument to anything.
Arguments against God on the basis of "suffering" and "evil" are not very strong...
I disagree. Of course if you're the kind of person that would suggest that god might be evil then such argument wouldn't be worth making. Most don't make that suggestion however.
I will leave you to stick to whatever it is you want to stick to. Kindly show the same respect.