I personally really like the way they've only shown Morgan sporadically and dramatically changed his character each time he shows up.
If you look at each season, it explicitly ends in a way that reinforces Rick as the main character of the show and makes a statement about the arc he has been through across the season. For the sake of my own thoughts, I'll go through each season, but feel free to ignore all but S5.
Season 1 sets the scene.
Season 2 is his processing of Lori's and Shane's betrayal, and Shane and the group in general's questioning of his leadership abilities and direction. The season ends with him being forced to kill Shane, turning Lori against him entirely, and the group's uncertainty greater than ever. His original moral stance - trying to patiently enforce and ensure the survival of the morals and democratic power structure from before the zombie outbreak - has also crumbled. Thus the season ends with him bitterly extolling the sacrifices he has made for the group in the rain in the dark on the roadside, and declaring himself a dictator over all who choose to live under his protection.
Season 3 explores what the ramifications of what the dictatorship he has proposed might mean by playing him against a genuine tyrannical ruler, The Governor, and, in the final stretch, he sees that he doesn't have it in him to rule like this and rolls it back (the last scene of the episode before the finale). His ability to lead effectively is also tested again as his fallout with Lori, still a thorn in his side in the early season, goes nuclear once she dies and he subsequently starts to lose it entirely. The season ends with him looking out over the prison, NOT seeing her ghost, and then with a peaceful shot of her grave, to show he's put this to rest.
Season 4 begins with him as a morally balanced and open leader who strives to create a peaceful community in this environment despite the challenges. Through the failure of this settlement, and the attacks by the Governor and Joe's group, he transforms into the fearless, scarily brutal pragmatist who is capable and willing to do anything to protect his "family". The season ends with a flashback of him putting down his gun and picking up farming equipment, before coming back to a caged tiger vowing vengeance.
Season 5 in its earlier half, further explores the new kind of leader he's become, leaving it an open question whether he has compromised his morals, whether he is now "too far gone" and has truly become a tyrant. The real challenge to this is how his new stance holds up when his group has to integrate with the Alexandrians who are relatively untried and innocent to the ways of the world beyond their wall. Deanna is effectively S2 Rick, and Rick is now S2 Shane. The latter season teases whether this integration is possible and if Rick and co. will resort to brutally taking over. In the end, they don't, multiple figures are spared, yet Deanna yields to Rick's moral stance and leadership style, arguably lending it some credibility, and allows him to kill Pete. The Alexandrians have accepted these new people as a scary necessity.
The re-introduction of Morgan in the finale was really clever because he hasn't seen Rick since way back in S3, and he has evidently managed to overcome his collapse and reaffirm a much more optimistic outlook from his experiences. By having him see Rick in that final moment, scarred, covered in blood, and shooting a man restrained on the ground, even though the finale was meant to assure the audience that Rick is on the right track, Morgan's perspective forces us to look at Rick and throws everything we've been led to believe into doubt yet again at the last moment.