I'm sure people have thought about it, it's just hard, annoying, and asking a lot of mostly unpaid OSS contributors. Many mod developers are high school / college aged.
Sandboxing Java code running in process requires ugly and obscure security APIs and restricts you to having to have a common modding API (Forge). Many mods use bytecode patching and would be broken completely.
Sandboxing Java code running in process requires ugly and obscure security APIs and restricts you to having to have a common modding API (Forge). Many mods use bytecode patching and would be broken completely.