I think the 50-135mm lens, although not extremely wide, is more than wide enough for events (not sure about weddings b/c I have not used it yet), and to be honest, it is a world away from the 70mm wide of the other lens (yes i can test this by putting my camera to 70mm.

)
When you are in a crowded event (let's say a festival), to get the 50mm equivalent with the 70mm and your subject (a human face) is about 4 feet away from you, you will probably have to move back (this is not scientifically accurate) about 2-4 feet to get the same FL.
I also pondered on this exact question several months ago, and in the end, it really depends on your style of shooting.
I'd say the 50-135mm by itself is a great lens for use for portraits (f/2.8 is nice creamy bokeh, although some may prefer even creamier bokeh), events, and gatherings (REALLY nice for this). It may be big compared to a comparable 50mm f/1.4, 77mm f/1.8 set up, but it is much more versatile and IMO the rendering and sharpness of the 50-135mm at f/2.8 seems better than the FA 50mm or 77mm f/1.8 (*hides*) although the 135mm end of the lens is not incredibly long for wild life of any sort (maybe zoo)
70-200mm f/2.8 plus a teleconvereter, probably also makes a good event, portrait shooting lens (although b/c it is longer not as practical) and a 1.4x TC will make it a good general action lens.