As far as I could tell all the scenes that Bell had with Ais had in the SO LN were in the anime adaptation of SO, as well all of the excessive romantic obsession scense that Lefiya had in the anime were in the LN and just as over emphasized. So that's a rather disingenuous point of contention to hold for the series.

I would also argue that the adaptations of both SO S1 and DM S2 weren't as bad as everyone is trying to make them out to be. And DM S2 couldn't have been that badly accepted because they announced S3 alongside airing the final episode. And I can see a SO S2 announcement coming soonish seeing as there's so much intermingling of the Xenos arc and the Knossos arc that they wind up spoiling each other. I can see them having a similar relationship to the A Certain ... series where Railgun airs well after Index in the real word, but Railgun is basically a prequel to the same season of Index.

I get that personally felt disappointed with the adaptations, but the arguments I tend to see border on objecting to the original content as much as what was actually cut. Personally I think the main issue with the SO adaptation is no one actually aired it. I didn't even know it was a thing until I went hunting for season one of Infinite Stratos and found Hidive.