Emm, honestly, I always picked Sunset as a thinker.
She gained empathy powers and can read people, but very often she's more into giving practical advise rather than emotional conseling.
For example, in Rainbow Rocks, she told to the girls that if they don't work their issues, the magic of friendship can go on the opposite way rather than being helfyul, which in turn allowed the rainbooms to defeat the dazzlings.
Inn friendship games, her first approach to Twilight was more into the "what are you doing with the magic" rather than the final heartwarming talk. She was concerned about the damage magic can cause. Now, we must remember than T or F doesn't dictamine more moralist or more logical by itself. Sunset's moral is about "everybody in the school being fine", which while it might be supported by usual F's, moralist and healthy T's pretty much go in the same route, usually in a "needs of many" way, and if Twilight was tampering with magic, then she should do something about it, even if it means not being that nice to this Twilight.
In Legend Of Everfree, she told Flash to get over Twilight because Sci-Twi was clearly not interested on him. Keep in mind she aimed to explain "Twilight is form another world, this isn't your Twilight" way and didn't sugarcoat anything.
It worths nothing that living in the human world alone for a time probably forced Sunset to mature some things, and as such she's more in contact with the four funtions, making her hard to pin her down at times. Notice how in-development characters are easier to pin down according the MBTI.
Sunset's biggest flaw comes into how prone tor age outburst she is. Because she tends to hold herself all what she can during a crisis, she tends to get on her way to act fairly irrational and incredibly destructive to everybody around. It should be noted that very often the biggests flaws of a person usually shines in the inferior sides of ourselves: Sunset is more of a pasionate yet levelheaded and rational being who wants to find the logical ways to solve problems, but under pressure her weaknesses comes from the emotional side of the spectrum, indicating that her Feeling function might not be at the high points, just more developed and well controlled under normal circumstances, and helpful when it comes to use them in the right moment.
In one short of multiple options from the digital series, her first answer leans more into the practical advise rather than emotional support thing: When Sci-Twi was confused with a text messages full of emojis than Timber sent to her, Sunset's answer was Have you thought about maybe asking for what he means?. She gave first before everything something pragmatical rather than emotional, you don't understand the language? ask to someone who knows it. And when Sci-Twi asked her how to say it in emojis Sunset decided to intervene. It makes Twilight unconfortable at first, but just because she's a T doesn't mean she's outright mean, and when things are cooled down she acts warm.
We can't also disgregard her time as an alpha bitch in the first movie, where Sunset was pretty much an unhealthy thinker who aimed for power and the recoignance she thought she was being denied too. And given that the more recent stories are trying to reconcile both characterizations, Sunset might still be a thinker after all.
Is just my opinion, but I often think that people expect F=warm T=cold. Fe is often seen as an empathy functions and all and some people relatate that with Sunset's typing as ENFJ, but that's not a golden rule. For starters, Si makes more sense for loyalty because of the guardian temperament, guided to preserve society in order to keep us alive and all, but the element of loyalty is Rainbow Dash, which is pretty much a dominant Se attention and thrill seeker and stereotypical speaking Se is far more vinculated for YOLO behaviors and personalities, and she HAS shown to deserve the element of loyalty at the same time.