Are there technical issues with doing video reviews of software?
I think it is mostly a structural thing.  Games generally involves simple interaction with a lot of similar content.  Hardware devices have a physical interface and while they can run lots of different software, the capabilities of the device are reasonably easy to describe.

For general productivity software, the interactions are complex, but not so deep, thus it is harder to review in video form.  You see many video tutorials about how to do particular things, but a review is concerned with glancing over a lot of information about the product and doesn't give much interesting visual content to go along with it.

For a game, you can show some gameplay while you talk about the review, but what do you put on the screen for a video review of say, Photoshop?  The main screen of Photoshop is the main screen of Photoshop.  You don't have enough time to show all the new stuff and if you don't have time to fully show it, then what do you put on screen while you mention the new things and how they work?

Try it for yourself, read a software review sometime and think about what you would put on screen while reading it if you were to produce a video form of the review.  It's really hard to come up with visually interesting content that would fill the space.  Now you could simply have a video of you sitting there talking about it, but that is slower to consume than reading an article and so doesn't add a whole lot of value.

There simply isn't really any interesting visual interaction that video can handle better than text and simple screen shots that can setup in advance and put into a written review do a better job of naturally showing how a new feature works in a concise manner than video could.