By the time I had enough stuff well past mythic to consider slogging through the current disenchant interface, I pretty much had no need to use it. Thats kind of a problem with the current system, it takes so long to extract those souls unless you have at least mythic +100 of commons/rares or mythic +20 of ultra rares that it would be nearly as fast just to do some battles with Valk and farm them directly. Having single-click for over mythic +4 might curb this a bit, since having anything at mythic +4 would result in small amounts of extra souls, but you could easily end up progressing beyond the need for significant quantities of souls by the time you can get them using this method, especially now that total amounts of glory keys may be going down and the system may be favoring gem keys and gold keys a bit more, which could make it less likely to get mythic ascensions in the rare/ultra-rare category far, far before commons as with now.
The one time I would recommend doing some disenchanting is after spending a bunch of event keys. Usually this gets a specific ultra-rare or two so far past mythic that it is worth the time opening the menu and disenchanting your extra copies. It might only save you a few battles, but at least the time ratio is of benefit at that point.