Yes, I see what you mean. I am not averse to introducing this change, if there's a demand for it AND preferably if someone tests it for me, for I don't have BGT. Okay, I'll look into this.
Right. So: from what I see, it is only possible to preserve full continuity for Xan, if I somehow take "Xan" object(not a cre, but a death variable) from the beginning of
BG2, and assign him Xan's dialogue(possible) and "O#Xan" death variable, which is - alas! - impossible ingame.
Of course, I could decompile all my scripts and change all occurrences of "O#Xan" to "Xan" in my .tp2 upon
BGT detection, add ENDOFBG1 checks and whatnot, but I don't see much sense in introducing such a drastic and potentially damaging change for the sake of keeping... well, practically nothing, because
1) most players use the tomes for themselves, so Xan's stats with high probability remain unchanged(in
BG2, his default stats equal those of
BG1);
2) Xan'll be stripped of his items anyway - see his
BG2 story. Besides, Viconia and others lose their items, too, for the story demands it;
3) the spellbook changes, true - but I don't see it as a big problem, since lady Yuth and other traders are abound in Athkatla. Besides, having only five/six spells per level helps preserve the game balance.
So, it is not going to happen. Sorry.