This would be an interesting idea, if anything. The thing is, this setup would leave some champions completely useless because their kits are too based on jungle/support, which would be dead positions. A couple of other things would be:
- Some large monster/monsters (like a dragon/baron) to have some large jungle objectives to keep things interesting.
- Strategic bush positions, obviously.
- A way to balance between having no jungle, and having enough space to keep cross-lane ganks from being overwhelming. If the lanes were literally right next to each other with no sort of jungle barrier, then there would be no way to stop a ridiculous amount of ganking, so the lanes need to have some organization.
- Balancing of characters so that a lot of kits could actually be useful in this mode. This may involve making lanes asymmetrical, or more objectives that different positions/kits are better at than others.
- Many smaller things like item availability, summoner availability, gold, etc.