Redoubts are very effective at their role. Each defensive building should have a specific role and specific units they are strong against. The primary defensive building for taking care of ranged shooters is the mortar, not the redoubt. Redoubts excel at destroying massed heavy infantry and raiders. The 30% research from the University that will be added in the future is more than enough buff, if you massively buff them you may as well remove Heavy Infantry from the game. That will mean even less German and Japanese nation players, which means less silk and salt.
I've come across many Korean bases were the player has selectively either not built their redoubts or upgraded them, presumably for the sole reason of keeping their WW matchmaking score down. Heavy Infantry/ Raiders are rarely used in War, so maybe it works. But without those redoubts, their Oil Refinery is a sitting duck in multiplayer.