This would be great to have, but keep in mind that Dave had to outsource the Android project. This means that in order for him to have a PC and/or Mac version, he will need to do the same, which costs money or worse yet, do it himself causing the updates to slow done as he is split on responsibilities.
Also, as for creating a Mac or PC app, it can be done from the ground up easily as a universal app, if the programmer knows what they are doing. I commend Dave for creating the Blockheads as a universal app, as it is much more work to accommodate both worlds at the same time.
As for the comment about Minecraft being a more difficult programming, this is most likely not true. There might be more features and more advancements, but without seeing the source code of both apps, there is no telling which one is smarter under the hood.