>>2133479
That's because it's not Remilia's primary and sole trait. For Tenshi it's pretty much all she is, her celestial background serving mostly to give her the power to get away with it and further empathise it because celestials shouldn't be bratty and immature.
Remilia on the other hand has a reputation built up, she enjoys playing the villain, she's arrogant and employs a colourful cast behind her. I'd need more information on Tenshi to really start to like her because as she's laid out she's just a upstart celestial given power through birth causing trouble for fun before going home. That's it. No real wonder in her history, no real mystery about her. She's just a quick throw away excuse to have everyone fight again.
I prefer her friend, Iku.