Have you talk to support about this? This poses a problem for me if the below discussion doesn't resolve this so please provide feedback. I do a lot of silkscreen work with cosmetic sketches. I use to be able to erase them easily with show/hide. Now that cosmetic sketch is no longer a "model annotation", this makes cosmetic (datum) curves a new issue to deal with.
Here is what I came up with. In the drawing, I created a layer called "HIDEME". I drag and drop the offending feature onto that layer. It shows up something like I posted below. You have to specifically change the feature to HIDE (right click and hide) rather than just the layer. I tried dropping it globally (onto the *.drw layer) but it wouldn't erase all the views.
Also notice the Layer Status Control dialog (from the layer tree Settings button, bottom line; drawing layer status) changes the way layers behave. You can have it follow the model but I believe the Ignore is the default.
I was hiding Curve_1 which is F46 in the drawing. Note that this is a layer in the individual view New_View_2. When I created the HIDEME layer globally in the *.DRW layer, it created one for every view.
I haven't yet gone back to start this exercise from scratch but I think you get the drift.
If you haven't yet started a case for this, I probably have to file one just to confirm this was the intended solution when they yanked cosmetics from the show/hide routine.
Can someone shime in as to how long the classic Show/Hide (with cosmetic feature) dialog has been removed?
This is Creo 2.0 Parametric
As for showing the feature, it is the exact opposite. I can turn the feature back on at will. I did add the feature after the drawing was set up and by default it showed in every view.
I worked with this a little more last night. Indeed, the layers are tied to the whole drawing, not just the views as the dialog might imply. I was able to force features erased in the model to be displayed in the drawing, however.
There is a lot of counter-intuitive actions going on though... an "hidden" layer lets you "unhide" features under it. That's just wrong 
