I have seen this pattern where を is replaced by の in many sentences that use a する verb. I got used to this construction by exposure and it has started to look less clunky and more natural to me, but I would like to know:
1）Is there is an actual difference in meaning, or at least in nuance, between both patterns?
2) Are both options valid in any situation or should I pick only one of them in any particular case?
I naturally would go with:
as I understand the structure of the sentence as:
（私たち）を （世話する）（to take care of us）
However, I see the following pattern quite frequently:
（私たちの世話）を （する）(to do the take caring of us)
Now, don't get me wrong, I would never translate this into “to do the take caring of us” but I would translate it as “to take care of us as” well, but hopefully you can see my point this way.
I think that what made it mind blowing for me was that coupling the suru verb as a noun to the previous word (the object, in my example 私たち) somehow “detaches” the verb from the actual subject (姉), but at the end of the day it's just a matter of getting used to it.
Finally, I suspect this is somehow related to the が/の substitution discussed here:
Thank you very much!