[anime] About the first seasons pacing.

There are a few criticisms out there about the pacing that the first season of the 100 Years Quest Anime had, some reasonable, some too extreme, but there's one particular thing some people say in terms of how they think it could have been better that I don't quite understand.

And that's the idea of the anime adding scenes to extend things out. A couple examples being showing the fight of Mira and Elfman vs. Skullion and Madmole onscreen, or having Georg fight Selene (or at least show him using a couple spells).

And here's the part that confuses me. Fairy Tail 100 Years Quest is a Seasonal Anime, and is it common enough for seasonal anime to add new scenes that weren't present in the manga like that for this to be a reasonable and realistic expectation?

I ask that as a legitimate question. I'm not trying to start a fight or call anyone out here but the impression I get is that such a thing is indeed not reasonable or realistic to expect.

I just want to get a gauge for if that impression is accurate.