Nope. I doubt magnified view would be useful in the situations I often encounter. My subjects move quickly and can be anywhere in (or out of) the field of view, for example ...
This is a small example of what can be done with a good optical viewfinder optimized for manual focus. With eyes that are well over 50 years old.
those are wonderful photos, that I could not achieve with manual focus on any gear whatsoever!
And yes, the strategy of "enlarged view around a selected focus area" is not suited to fast-changing scenes; selecting an off-center magnification zone on the E-M5 takes me several seconds at best.
But let me look forward to what EVF technology can hopefully do for us, even if current implementations are not quite there yet. To focus quickly on a specific off-center feature like a bird's eye, we lose the focusing aids at the center of an OVF or the "magnify when focus ring is turned" mode of an EVF, so have to rely on judging the sharpness of the VF image itself (unless focus peaking can still help off-center; I have not tried it). So the main virtue we want is a large, sharp image -- something that has gone downhill in the transitions from high magnification OVFs designed for manual focus to the somewhat smaller OVF images of autofocus 35mm format SLRs and then to the even smaller OVF images of digital SLR's in the now-dominant "smaller-than-film" formats. Compared to that, my guess is that old manual focus SLR OVF are still the best, but the best of the new EVFs (like the Olympus VF-4 accessory EVF, and maybe the forthcoming Olympus OM-D E-M1) are about on par with the OVFs of 35mm format digital SLRs and ahead of the OVF's on the smaller mainstream format digital SLRs.
Since an EVF can be designed to give an image at any combination of size and brightness, regardless of sensor size, my hope is that some future EVFs will offer images at least as large as any OVF has ever offered. My guess is that this will never be a mainstream option even in 35mm format, since even digital SLRs all have OVF image sizes smaller than the best of the older manual focus OVFs, but there is hope that some high-end accessory EVFs could be targeted to this more specialized market.
Meanwhile, I wish that there were milder magnification options like 1.4x and 2x on the OM-D E-M5: that would greatly enhance manual focusing, giving an image bigger and more detailed than any SLR OVF ever did, while still covering most parts of the scene where I am likely to want to focus. And I want the option to keep an outline of the full scene around the magnified image, so I can still check the overall framing at the same time!
P. S. Here is how I use magnified live view to focus manually on an off-center subject; the traditionalists will probably not like it!
With appropriate settings in advance:
1. use the rear screen initially, and select the focus area by touching it on the screen
2. press the "magnify" button (and swap to the EVF if desired)
3. focus manually, on the magnified view of the selected region
4. if needed, touch the magnify button again to return to the overall view.