I like the idea in principle but it needs tweaking or adjusting because its currently very very strong in certain situations and might actually shift the late-game war meta.
I think it is great idea for new players. I think people forget we are the (mostly) comprised of the vocal hardcore subset of the community. I think this will be great opportunity for them to somewhat even the playing field. I'd imagine quite a lot of them get quite disheartened when they login for the day and see they have been cleared and farmed while asleep by some more active veteran next door. Currently quite an effective strategy at all stages of the game for active players is to essentially work out when your opponent is asleep and then attack them at that point. Its understandably viable but in an ideal game it shouldnt really be a go-to tactic for defeating your enemies. Can hardly brag about being a good player if you just rely on being more active and attacking people while they are asleep lol. It should be something that is doable but has downsides, a night bonus solves this problem quite nicely in principle.
However i also think this is again something thats not been thought through to its fullest conclusion by the development team. Talking primarily from the pov of mid-late game this makes defending incredibly more powerful and accessible for everyone, particularly for people like myself who usually coplay most of the time. This is because the biggest problem most people have is being burnt out of the game. Everyone has thresholds for what they are willing to do for the game in terms of time/money/etc and once that limit is reached them its pretty much gg and they lose. Often wars are determined by which tribe has more stamina than skill, the tribe that (as a tribe unit) has the most time they are willing to invest into the game will win, not always but often. But with the new night bonus it becomes incredibly easy to avoid burnout and its also pretty easy to exploit it like so:
The majority of the playerbase is EU time-based, i'd say roughly 60% or so and most ops will land on an eu-favorable timescale (no data just eyeballing and experience). Given those two facts the best time for me to set my nightbonus will be 16:00-00:00, even though i am awake during those times. This is because it basically stops all EU evening ops and greatly lessens the impact of EU morning ops. Half of the damage from an OP comes from the follow up after nukes land. So long range nukes hit long range def then over the next X hours local nukes skirmish with local def and you try and get caps that way. By setting my night bonus to start from 1600 then that really limits how much local skirmishing my opponents can do to me. Essentially now the only way to OP me will be to time it for EU night time. Which is fine for me as i always play with an american CO and additionally given most of the playerbase is EU timebased its always quieter and easier at night (within reason). So its basically a win/win. I can now relax every evening and not have to spend my leisure time each day defending. It will probably reduce my workload by at least half. That means realistically i wont really ever burn out because im always going to have a break from the game. Which invalidates pretty much the entire attacking meta in lategame wars. I dont mind leaking my timezone or future plan to the public because there is nothing anyone can do about it
And if my american co wants a break for his/her evenings? Well then we can just rotate around weekly no problem
So all-in-all. Great change for new players. Fantastic, game breaking change for nerdy defenders like myself. It will now be much much harder for attackers to overwhelm defenders through brute-force and activity (good in principle). No more lazy yolo attacking, you have to fight people face to face and see who has the most skill.
But this is actually a problem because defending is a lot easier than attacking once you know what you are doing so i think this will tip the balance too far towards the defender. For right or wrong currently the game design is balanced around activity and this is really unfair to give such an insanely overpowered tool to the defender without any compensation towards the attacker.
I would suggest to compensate attackers by something like a flat 25% increase strength to rams. This shouldnt impact new players too much but will help mitigate this incredibly powerful defending tool for the mid-late game. Also helps to flatten the ridiculous PP walls strategy which i dont think literally anyone enjoys.
edit
As others have said it shouldn't be retroactive. Not fair to people putting in their hardwork and to have the meta rug pulled out from under them mid world. New worlds only please (or at least only w111 because baby world anyway)