"no shame in reusing an engine" -- Yeah that's absolutely right. However, MM78 are generally thought to be in decline (compared to their respective predecessors) while BG2 might be better acclaimed than BG1. The short development duration of MM78 might be partially to blame. I justed Googled "game development cycle duration", it quotes an answer from
https://www.quora.com/What-is-the-typic ... nt-project which says "Most AAA games take 18 to 36 months to develop."
Indeed :
MM6 ---13 months---> MM7 ---9 months---> MM8
BG1 ---21 months---> BG2
[Edited: it seems MM7 was released 8 Jun 1999 rather than 2 Jan 1999, these intervals have therefore been corrected accordingly.]
The short duration of game development and the reuse of the old engine, this could be a bad combination because developpers could seek some "shortcuts" and reuse not only the engine and the system but also many other things which are not supposed to be reused. For example, has anyone here ever noticed the maps of the cave of Stone City in MM7 and Dark Dwarf Compound in MM8 are almost exactly the same?
http://mikesrpgcenter.com/mm7/maps/stonecity.html
http://www.angelfire.com/games/mm8/darkdwarf.html