OP, When you say add-ons are you talking about mods or DLC?
If your talking about official DLC, then go nuts. You will have both PC & Console users approving/disapproving of your ideas.
If your talking about mods, the reason ideas might be shot down is because mod creators are well aware of the restrictions and requirements of the game engine and the modding tools.
To my knowledge console software has restrictions on accessibility to the OS/filesystem. So running things like script extenders or replacing the EXE won't be possible. Not that it's technically impossible. I imagine these are more like light software restrictions, and more agreement restrictions between developer & console maker.
There are also hardware limitations on consoles. The only hardware upgrade I'm aware of on consoles has always been increasing Hard drive space. Every Xbox has the same video card, same amount of RAM, etc.. and these don't change. If mods are designed for systems that exceed these requirements then they won't work on consoles, or at least not for an extended period of time. I was surprised that the new generation of consoles only went with 8 gigs of ram, this is about the lowest amount of RAM you can buy in a modern PC. For example: The PC I built 8 years ago had 8 Gigs of RAM. The one I put together last year has 32Gigs.
Disclaimer: Hardware limitation paragraph is not meant as flamebait. The restrictions on hardware is what makes consoles so popular, and why there are fewer bugs on console only games. Developers know exactly what their systems are capable of and can design within those limitations. The amount of testing can be drastically reduced with the same level of quality, etc..