Sort of. Arthas was notably much more down-to-earth with his subordinates and his people prior to investigating the plague than the rest of the royal family was known for being. He was also very immature even as an adult and. in the novel, displayed a marked fear of responsibility.
His relationship with Jaina was a perfect microcosm of problems that would arise during the investigation where he constantly got himself in over his head, only to immediately shirk his responsibilities as soon as he realized how in over his head he really was, instead seeking out silver-bullet fixes to his problems. Arthas was also shown to be highly egocentric--he either couldn't, or wouldn't, understand why, immediately after having sex, Jaina would be so hurt about his sudden decision to dump her and remain friends when she brought up potentially having a family together, and expected there to be no awkwardness or hurt feelings on her end; if I recall, he indirectly blamed her for his own hurt feelings on the matter once he realized how much he'd hurt her.
He also had a bad habit of wanting to have his cake and eat it. When he rekindled his relationship with Jaina, he wanted it on his own terms and for his own comfort, and again, she was expected to go along with his wants/needs. He never quite got to the point where he had problems with empathy, but there was a marked tendency toward selfishness and a level of cowardice in his psyche, as though his development as a person were permanently arrested when, as a teenager, he had to kill his beloved horse after breaking Invincible's legs during a nasty spill in a snowstorm.
It's these significant character flaws, his egocentrism and arrested development, that shirking of responsibility and fear of the unknown, that caused him to react so poorly to the plague. He was completely out of his element for the first time in his life, and he wasn't in a position interpersonally or by rank where he could simply assume the plague would abide by his wishes until he was ready to grapple with it like he could with his relationship with Jaina or his duties as a prince and paladin. It was Invincible all over again.
That said, he wasn't malicious during the Culling. He was in despair, because he was helpless to help the residents beyond giving them a swift death and preventing them from being risen as mindless slaves. He had a no-win scenario, and he felt like Uther, Jaina, and the Light all betrayed him in that moment. If he left things in Stratholme unaddressed, that city of the dead could spread out and rapidly escalate an already-precarious situation. Remember that this is the same Arthas who swept Jaina off her feet, fucked her, and then immediately shrank back and wanted to just be friends again because she wanted to advance their relationship beyond his timetable, once he realized what sort of responsibility he was about to take on himself. That Arthas had to take responsibility for an entire dead city now, and that broke him after the constant stress of fighting the plague began to fracture his mental state.
In Northrend, he still treated his men well enough. Even broken and half-mad with despair and vengeance, Arthas still cared about the people of Lordaeron and the soldiers fighting under him. Yes, he took on extremely morally-dubious and outright immoral actions like betraying mercenaries who had helped him survive, burning down the only way his men had to get home, and abandoning his men to hold the line while he, Muradin, and a small squad set out for Frostmourne.
But it wasn't until Frostmourne absorbed his soul that he truly became evil and malicious. Until then, he was simply a spoiled kid who was completely out of his element after spending his life surrounded by people who either overlooked, ignored, or nepotistically disregarded his serious flaws that led to him breaking under the first time in his life he really felt the pressure of leadership and the responsibility of his rank.