I don't think you quite understand the problem. It's somewhat hard to explain. I used to work with Maya 2012 and when I was working on a polygon mesh and, for example, had the translate tool active while in vertices display I first could select any number of vertices (with the tool active) and then had to click on the tool center or on one of the arrows in order to translate the selection. Then, if I wanted to de- or increase the selection I could do that while still in the translate tool. No need to activate the selection tool change the selecting and return to the translate tool.
Now in Maya 2015 when I am in the same situation I can only select multiple vertices when I start the selection from outside the mesh. When I start inside the mesh only the single vertice closest to the cursor (the one that lights up in red because of the new selecting preview) is selected and the translate tool is active right away as if I clicked on the center square of the tool at the same time. Now wherever I click within the mesh the same happens, one vertice is selected and starts to move in all axis right away.
I think this might be a hardware problem, graphic card related probably. I tried Nurbs too (I usually don't use them) and noticed that then the problem does not occur. I can select the control vertexes while in translate or scale or rotate mode, use the tool and then change the selection without deactivting the tool the way I am used to. However when there happens to be another Nurbs object behind the one I'm working on it seems to get selection priority and I can't select the CV's on the object I was working on, pretty weird.
Like I said, it might have to do with my new hardware. I work on windows 8.1 and have a Nvidia Geforce GTX970, not a Quadro.