Beyond the Ilia/Troi dynamic with the respective characters at the start, I didn't think there was a whole lot of similarity, honestly. The power dynamics were totally different. Decker had already "made it" but was now a demoted Captain, seething inside that he was better equipped to handle the mission than an Admiral who came in throwing his weight and reputation around. In Decker's mind, Kirk had to prove to HIM that he deserved to be there, and honestly I don't remember Kirk really making a decision in the film that would have. He usually made a bad decision and lucked out.
Decker only lost that anger only when he found something more important to him to focus on - bringing what was left of Ilia out of the probe. He saved humanity from V'Ger almost as a side benefit to his obsession with her/it.
Riker came in a fast-rising ambitious upstart who was trying to prove to everyone that he was good enough to be a Captain - competing not with the CO, but competing to become the next CO (of that ship or more likely, another) As the series wore on, he proved himself to the crew but lost his sense of ambition, which depending on your personal opinions as a fan is either ridiculous character regression, or merely an acceptable shift in his goals once he got there.
I would say it was no later than The Icarus Factor, when Riker was offered the Aries and stayed - that's when he became the anti-Decker. There's no way Decker, in that situation, wouldn't have jumped ship to get as far away from Kirk as possible, no matter what.
I choose to believe Will found a 'home' of sorts on the Enterprise and his decision to stay was down to how he felt about the ship, the crew and his captain rather than a lack of ambition. There's also the school of thinking behind being the first officer of the flagship is a better position to be in than the captain of some irrelevant Oberth-class starship on the edge of Federation space doing nothing of note.