Certain multiclass combinations from the plain PHB as well as from expansions are unavailable in BG.
I always found it sad, that in most AD&D computer games my favourite multiclass combination ist missing:
The neutral good half-elven ranger/druid. In the forgotten realms setting this is specifically the order of the Shadoweirs, praying to and fighting for Mielikki (the equivalent of Ehlonna in the Realms).
Probably this is due to page 44 "multiclass" only saying "ranger/cleric and fighter/druid", and most readers miss that page 22 (half-elves) says, that they can be ranger/clerics as well as ranger/druids.
Later products (the "complete" classes series - "complete rangers" / "complete druid" confirm this and even add more details, and the FR "Faithes & Avatars" allows those ranger/druids to use longsword and bow in addition to the druid weapons. Desired behaviour:
Add the missing combinations from the PHB, maybe even those from the "complete classes'" series.
Pleasepleaseplease, can you fill this gap? It wouldn't be difficult to implement and the total incentive for me to completely playtest through BG:EE with such a character :-D (although I just played through Tutu tweaked and are halfway through TOB tweaked).