A lot of players in top alliances are spoiled by all the boosts constantly available. Such a war will be a real eye opener for them. They will certainly have to adapt first before they are able to raid 100% every time. I am sure there will be players who now completely are dependent of those boosts and aren’t able to adapt at all. They will have to ask others which troop/spell combo needs to be used to beat bases, since the boosted combination of troops definitely isn’t going to work at all.
I agree that fair/good raiders will beat any base when there are no boosts. Main problem for a boostless season is that spells are overpowered. They are able to kill most boosted troops, so unboosted ones in defense are killed completely by them for sure. So that’s something that needs to be taken care of during such a season to balance things out. If the malus would be lower strength of spells (so that spells aren’t able to kill all maxed troops with one single shot) or only two spells max per raid, such a war would become suddenly very interesting.
With such a malus for raiders I guess not all raids will be as easy as some players think.