I have a Panasonic GH2 and I couldn't be more happy with it. As for slow... whether you are talking about focus speed of aperture, I wouldn't agree on either.

In terms of focus speed, the GH2 is very quick with the latest generation lenses, apparently rivals most entry level DSLR's in most situations. As for aperture, yes, currently there is a shortage of fast lenses in the tele region(though the new lenses Pana is releasing soon should fix this) but the shorter lengths are covered with some great compact lenses. For my usage the shorter stuff is more important as it is usually what you want indoors. I've got the 20mm f1.7 lens and it covers me well in this regard, though it does suffer the occasional focus hunting issue. I've got the 14-140 lens which to me is a fantastic lens, offering a useful range, fast focus and good video usage, I use it for everything except low light or fast stuff.

As for the whole optical vs EVT, my personal preference is that I love the EVT. I specifically waited for an EVT(I was waiting and wondering BEFORE the first interchangeable lens EVT's were released) camera that met my needs because I didn't want a clunky mirror that flips in and out of place while taking a photo and I prefer the what you see is what you get. Of course, it's all a compromise and the biggest advantage of a real DSLR in my opinion is that it is a little more friendly for manual focus but given the readers question, I doubt that this will be a common use case.

Also, a good mirrorless camera(GH2) will beat a DSLR for video. This is because when recording video, the DSLR can't use it's phase detect auto-focus system so it's severely hamstrung, it has to use contrast based focus like the mirrorless.... only the current generation of mirrorless cameras are much much better at doing contrast detect focus because their manufactures have invested a lot into this.