>>718764224
TR-8R is a case study in how to make that sort of reception happen organically instead of trying to force it.
>dramatic entrance, shouts a challenge to the protagonist before throwing away his gun because he wants to beat the shit out of the guy with his cool electric baton thing
>this entrance also establishes solid motivations for his character, i.e. that he's mad as hell at Finn
>willingness to go baton-to-blade against a guy carrying a lightsaber and has just killed someone with it gives the impression that TR-8R has giant brass balls
>underdog energy from being a faceless generic stormtrooper in a franchise where generic faceless stormtroopers exist purely to do nothing and get killed by the protagonists in huge numbers
>actually does beat the shit out of Finn and would have killed him without outside intervention, quickly and suddenly established him as a genuine threat (also helps that Finn isn't a very popular character so people enjoyed seeing him get smashed)
There's a lot packed into that very short scene, while as others have pointed out Captain Phasma spends all of her screentime either standing around doing nothing or getting effortlessly defeated by the main characters two movies in a row.