less bugs? with an Elder Scrolls game? haha, surely you jest!
anyways, not likely.. the 7th gen consoles had been around for quite awhile at Skyrims time of release, they knew how to work with it and how to trick it to do things better.. the 8th gen consoles being rather new, they haven't fully mastered that yet (notice how games coming out toward the end of a consoles life are usually much better than its launch titles? yeah, thats why, as time goes they figure out more efficient ways to milk every last drop from the hardware)
and newer more powerful consoles don't automatically mean a bigger game.. with more processing power comes Graphics advancement, Audio quality, some rather beefy cinematics, new animations, and some very script-heavy features. all of which take up more space on the disc than it would have for its predecessor.. (if more powerful consoles automatically meant bigger games, we would have 4 entire provinces in a single game at this point compared to Morrowind)