#4 Laforge - Despite whatever short comings the character had, they did invest in him a great deal, & though episodes that centered on his social traits were dull, there were many episodes in which he was featured really well.
The Mind's Eye, Identity Crisis, & The Enemy are all really good, for example, but more than being useful for a small amount of focal episodes, which can also be said of Crusher or Riker, he was also one of the integral people that the dynamic of the crew was really set by.
Face it, until Laforge there was no such thing as "technobabble", & that's because most actors, quite frankly, couldn't deliver it interestingly enough to merit putting it in there, but Burton delivers it so effortlessly, that it doesn't bore, & instead becomes the backdrop for the stories
#3 Worf - Worf is really one of only 2 characters on TNG that got a full blown character arc, & it stands out as being a substantial part of the quality of TNG on the whole. Starting with
Sins of the Father in season 3, & carrying through seasons 4 & 5 with
Reunion &
Redemption. There was a real sense that this character had ongoing growth, So much so that season 6's
Birthright &
Rightful Heir make use of it further.
In a way, when you look at TOS, the one alien life form that is explored the deepest due to Spock's featured presence, was the Vulcan, & in TNG, thanks to having Worf aboard, the same is true of its relationship to the exploration of the Klingon culture, which was far more intricate than it had been presented previously, or in short, TOS is to Vulcans because of Spock as TNG is to Klingons because of Worf
#2 Picard - Let's just come out and say it. The actor behind that character just plain made you want to watch him more than any of the other characters, whether he's doing things as profound as being tortured & interrogated like a war criminal, & overcoming the horrors of being victimized by The Borg, or things as silly or mundane as taking down trilithium resin thieves, looking for the Tox Uthat, or having some alien try to force him to fall in love with her
His presence was what made all those things interesting. You couldn't ask for a better actor to sell Star Trek
#1 Data - Well, here it is folks, the only character arc that ever mattered to me in all Star Trek. The exploration of the soul of an emotionally bereft man. People get confused by it, because it seemingly makes no sense. Only after you are willing to admit what no one admits can you begin to understand the character arc
As much as it is professed otherwise, by everyone, Data does indeed have emotions, emotions which are so microscopic in presentation, that no one sees them or recognizes them, including Data himself, & as I see it, That was Soong's plan all along, for Data to discover his emotions incrementally, so that he could have the benefit of learning about them fully, before having to deal with them, & risk losing himself to them as was the case with Lore, who's only flaw was being a slave to his emotions
When you look at it that way, The Data saga is one of the coolest things Star Trek ever did, even if they did tend to muck it up a bit in the movies, like they mucked up everything else. My favorite reference to point out Data's emotions is the scene from
Data's Day where he dictates a log to Maddox
It is fortunate that I am able to perform my duties without emotional distractions. If that were not the case, a sudden course correction toward the Neutral Zone would make me very... nervous.
Then he takes note of himself unconsciously tapping his fingers on the console, which is clearly to indicate that he recognizes his own trepidation & distraction by the event. There it is, the infinitesimal emergence of an emotional being