[color:"orange"]how hard is this to test for?[/color]
Not very hard, assuming you have time to do so. CDV released the game early, requiring quests be dropped and the ending rushed to meet their deadline.
[color:"orange"]just because CDV is out of the picture (correct?) for Beyond Divinity does not automatically mean the patch support will be better.[/color]
They are out of the picture for beyond Divinity. Unlike other game developers, Larian released a couple hotfixes without any publisher support, and did much of the testing on the patch, which CDV was suppose to be responsible for. With Larian having more control over the release, and (from my impressions) better relations with publishers who actually intend to promote Beyond Divinity, I can't see how initial testing and patch support could fail to be better than with Divinity.
