I have the strong feeling there are some bad memory leaks in ArcGIS Pro that need fixing (ArcGIS Pro 1.2). I have worked on the conversion of a tool that now runs in both ArcMap and ArcGIS Pro, and that needs to generate a couple of hundreds of layers in the TOC, setting symbology and definition queries. This runs fine in ArcMap, but it simply won't finish in ArcGIS Pro. It gets stuck somewhere in the process, with memory soaring above 6-7GB.
When I limit the number of the layers to generate, it may finish.
But after generating a small number of layers (+/- 15), I accidentally opened the attribute tables of all the layers at once... (which reference a relative small dataset of +/- 50k records). ArcGIS Pro dutifully started to try to open all of them, but it was terribly slow, despite limited number of records and fully indexed fields. Not wanting to wait for this, I hit the close button of the last opened table still in the process of opening, and subsequently, ArcGIS Pro became totally unresponsive and memory went up to 13GB before I decided to kill it (machine has 16GB).