I have seen many people complaining about difficulty getting into invasion and wars. Although I can understand their point of view I also understand the controlling companies need to find best players available.
Solution I see as possible way to increase activity and experience for lower levels/under geared players is design small versions of both these activities in uncontrolled zones like cleave/Eden/SM.
This would add new content and a way to temporarily control a base in these zones, so players would enter a war to capture a base controlled by corrupted enemies, similar to war and then later an invasion would happen.
The three zones all have different levels of enemies and could offer a lot of different rewards like craft mods currently stuck in low level expeditions, faction tokens, gypsum, gold, rare items linked to the areas(corruption/angry earth/ancient).
Each zone could rotate to different forts or locations on current map everyday or every other day with 3 possible locations on each map. Different types of events that play out close to war and invasion but on much lower requirements but as under gear players could never meet current requirements due to current res pawns in wars from controlling groups being unbalanced and invasion overturned until you have trophies and enough dexterity freaks.
The goal is to simulate the experience in a fun and engaging way that encourages players to improve gear and want to do the harder content.
SM can also be higher level content for max players to be challenged and reward high level loot