I don't know if it would be jarring in such a way that it would be a deterrent.
Act IV and V are really the strongest albums from the Act series. I'm sure there are plenty of people who disagree, but I am coming from a place of self expression, or more specifically, rating them on the question of "Is this record what I wanted it to be?". Acts IV and V hit that mark at about a 95%, where each record before it had a somewhat lower mark, in hindsight.
Because of this perspective, I would want to start someone off on the best foot possible. I am not sure having someone experience my catalog in order has any other value beyond that of being interesting in a biographical sense. If they are interested in the story, I still believe starting with Act IV will yield a more interesting experience than starting with I. If they aren't interested in the story, I don't think its necessary to sit through 3 hours of material before you hear, what I consider, to be the most thoughtful output of the band's discography.
As for the reasons I think the narrative is more interesting, but I am just going to say for OP, SPOILERS: [SPOILERS SPOILER SPOILY SPOIL:](/s "If you are coming to the party with fresh ears/eyes/thoughts, and you approach it from the order of IV - I - II - III - V, the story goes a bit like this:
IV: A man returns to a familiar place, showing a heart with a disinterest in love, and showing signs of ambition. His war hero status gains the attention of the town's priest. The priest suggests the man use his status to do some good in the city, and, with the priest's help, he could achieve a high official status in the town. He wins the position of Mayor, and just as he is about to use his power for what he THINKS is good, the priest reveals a knowledge about the man's duality - and the truth is so damning, that it cements the man under the priests control.
So, if you start here- you end the album with a question- "Who is he?"
I-III: You learn who he is- why he is the way he is - why he would want to use his power for good- why he considers THAT to be good - etc... you learn everything about him, but its all background information if you think about the most important events of his life.
V: Coming straight from the aftermath of Act III, to finding Hunter in the desolate state he starts Act V off seems fitting, to me. You remember what he did in Act IV, but you are coming from the chaos that lead him there... and, you spend most of Act V with Hunter lamenting his own past - damning his current self for the crimes he feels he committed against his younger self... and by the end of Act V, he is acting as the human being he was during Acts I-III.")