Unity supports more platforms though doesn't it?
Eg it doesnt look like UE4 supports Linux unless I Google failed
I like the idea of promoting platforms to keep windows and DX with a competitor.
UE4 does support Linux in its current state, and has full OpenGL support. But it is missing a dedicated editor, which they are apparently working on. Though it is possible for developers to try and compile the editor for Linux themselves, and there has been some success with it. The officially supported editor hasn't arrived yet, but cross compiling does work.
On the Unity side, games can be compiled to run in Linux, but unfortunately they do not have a native editor yet, nor do they seem to have any plans to port one. Which really sucks on their part. This takes away potential developers who like to work under Linux. Some people have had luck running the Unity editor under wine, but that is really not the greatest solution.
Outside of that Unity does still support older PPC architecture and works with the PS3, Xbox 360 and the Nintendo Wii U. It also supports the Vita and 3DS, which UE4 does not. Though yet again, since developers have access to the UE4 source code, it is possible to try and port UE4 to those platforms, but Epic has no plans on officially supporting them. This is why some developers like NetherRealm Studios are sticking with UE3 for a little longer. They can still make ports for last gen consoles.
Depends on if 5% total revenue versus upfront cost works out better for you in the long run or not, but this MEGATON regardless
Interesting point. But I think for developers that are trying to break into the industry the 5% cut may look more appealing.