There are absolutely no limitations in the Devkit. You cant edit the sourcecode of Conan Exiles. But I did not want any modder, including me, to create compiled code running on others machines and do crazy “things”.
Blueprints are running in a virtual machine, so there is some kind of “b-u-ll-s-h-I-t-filter” that i really love to have!!! And thats how modding (by Epic) and Steam works.
And there are no limitations except some kinds of access to the DataBase.
You can change, rebuild, reuse or whatever you want.
You want negative gravity at some areas. No problem. You can do it. You want flying islands,… No problem, too… Seamless servertravel… You need a bunch of time, but feel free…
Oh… Mounts? Wtf. You can create mounts. You might think about a combat update. How to firght on mounts. How to fight Mount to ground and vice versa. How to beat down players from mounts. You can do that. There is no limitation, too. You want to ride close to lightspeed without falling through the map. Thats no problem, too. You can set the whole level to be completely loaded by the client. And you can do that all in blueprint, there is no need to have access to the core.
So in my view there is no real reason tho have access to the core. BTW: If you need something really speacial (and its not a completely stupid request) the Devs help, if they can.