I think if there's a problem with his delivery, it's more in line with the voice director than the actor. Yes, he's just about too measured at times, and while I think that the deliberate manner of speech was an intentional effect, it does come off as dry at times. On the other hand, then you have the scenes where he's really mad, or even yelling orders on the ship in contrast... it doesn't seem like it's a problem with the actor himself, IMO. I think part of it might come from the difference of style speaking Kanien'kéha vs the inflections of English.
Summoning of Spirits - The Tales Music Remix Project http://tales.ocremix.org/ Over fifty free tracks from ToS and ToP!
He's not too bad during the cutscenes, but in everything outside of the main questline he is shamefully monotone and robotic.
I think it's because he plays very well off Haytham; a father who's educated and sophisticated, has more experience and information vs. his young son who doesn't quite get it, so his stiffness comes off as rage.
But when he's with other people, that stiffness is just, well, stiff.
I couldn't decide whether Connor was supposed to have that halted cadence to his speech or not. Ubi could have intended for Connor to sound like that since English was his second language and taught to him by someone whose second language is English. But I can't help but feel that it wasn't this, but poor voice acting or voice directing.
R.I.P. Junk Bludgeo'd For Hammer, But Always In Our Hearts. 176 Damage, Nevar Forget.