Hi Roland / Fernando,
One thing about last node is that it's a representation of output, it's node a real aggregation or a real projection but a representation similar to make easy to manipulate/rename before went out on semantic. Is also the only one that you can switch between projection / aggregation.
This last one wasn't here since SP3 or SP4 if I remind well...
About the beauty visualization of filtering against the box to direct edit expression is the same since ever. Initially you can do it beaty but if you want one time to edit without the wizard Studio alert you that after you confirm the only way to maintain is manually through expression.
Of course, if you start directly on expression you will not see the option to filtering with wizard.
Regards, Fernando Da Rós