Even the lead man behind PeE2 cannot say why it flopped. Graphics? Gameplay? Genre fatigue (doubtful because of DOS2 success)? Bottom line is, PoE2 was very BG2ish and it failed, so hardly a good example to follow.
Originally Posted by Adgaroth
I've only played one GoW and regardless of gameplay mechanics all the games look like part of the franchise/series to me. BG3 don't, that's where the dispute lies.
Story and setting are enough to connect BG2 and BG3. Unlike GoW and Witcher, there isn't a character that is the symbol of BG. If the central character in BG1&2 was Drizzt and BG3 had used him as well, the games would instantly be connected in the manner you described; but there isn't something like that to connect them. Gameplay and graphics/design do not need to be similar, especially so with them being so far apart.