I don't know what is considered age appropriate, let alone gifted level work. It just seems ho-hum imo, especially considering the arguing, whining, and effort it takes to get her to do this.
Those examples are very good for the beginning of second grade. If her classmates are writing pages and pages it could be because they're unusually talented and motivated when it comes to writing. Or it could be that they're just really long-winded and add lots of filler and repeat themselves a lot. It sounds like your daughter's style is just very pithy and concise.
The arguing and whining would be my concern rather than the quality of what she's producing, given your examples. Is it the composition that's difficult for her or the act of writing? Is it easier for her if you scribe for her?
One thing I've seen, having worked and volunteered in quite a few public schools, is that writing in elementary school is generally barely *taught* at all. Even teachers who require a lot of writing from their young students don't seem to actually teach them what good writing is. I've heard teachers say things like, "You need more details, make it more interesting, and don't start all your sentences with 'I'". That's not very helpful!
I think classical educators are onto something with teaching narration, dictation, and copywork in the early grades without requiring original compositions until the grammar stage is complete. Certainly there are naturally talented young writers who should be encouraged to write whatever they like, but average writers and those who struggle should receive more direct instruction before being expected to perform.
