Would it make sense from a lore perspective to have an Iksar Monk instead of an Iksar Bruiser? I ask because my Iksar on Antonia Bayle, Sothikor is an Iksar Monk. Would a Troll ever logically earn the title "Knight Captain" (I know Bayle preaches D'lere is bad, not the people? It seems racism might hold him back. Although my Troll Knight-Captain is far more civilized than the rest of his people) I ask, because my Troll Berserker, Gumgan of Unrest has earned the title.
From what I understand both your points would have merit (Iksar would stick to Monk and Trolls would not rise very high) but only in the pre-cataclysm world. Since the events that split EQI and EQII things are a little more up in the air and from what I can gather Iksar are a lot less organised and Lucan will make use of any capable pawns. So in my opinion it is perfectly feasable that an Iksar without the access to formal training would lean towards Bruiser and a Troll with the right ammount of loyalty and ability would certainly rise through the ranks. Hope this helps.
In EQ1, Iksar and Humans were the only races that could play monks. The Iksar, historically speaking..have been monks for a long time. There's some lore in Kunark about them, somewhere. But they had a caste called the Swifttails. Although they, like all the other Iksar in EQ1 were typically evil. But, being a Monk is as natural to them as being a warrior, or anything else. As for trolls - not sure. But the Iksar monk is definitely fine.