Gamebryo was state-of-the-art when [i]Morrowind[/i] came out. By the time [i]Obilivion[/i] rolled in, it's nearing obsolete. Beth did pretty good on improving Creation engine from TES5 to FO4, beside the bugs, which are pretty much standard issue with every Bethesda release. Id5 used for [i]Wolfenstein[/i] has the best graphics they put out, but then again, the scale of [i]Wolfenstein[/i] was minuscule compared to Fallout.

Update: Next IC arriving tomorrow.