Hi Donn
both data import functions are completely separate and independent features.
The server side import was meant to provide a fast way to import server side data. Flexibility and control was not much of concern with this feature.
The client side import is focussed more on the use case of easy, simple data import e.g. for a PoC kind of situation. Once-off-imports I would call them.
For "proper" data integration - and your questions indicate that you have the requirements for flexibility, ad-hoc transformation and data parsing - SAP HANA provides the SAP HANA Enterprise Information Management option that allows to do such things.
If that's still not sufficient, there always SAP Data Services.
I am quite aware of the data import features of other DBMS and all I can say to this end is that the overall development for this capability was done with the two options I mentioned.
Hope that helps a bit though.
Cheers,
Lars