Sexercise (Kylie Minogue) was hotter than either of those videos even with the large disparity in quantity of ass contained therein. They're all terrible, but at least Kylie just focused on the reason anyone is watching the damn thing. Well the JLo one did as well but meh it's not especially hot, it's just their asses in swimsuits while they alternate between standing and crouching (not that the Kylie Minogue one is much more than that either).
Anaconda easily has to be one of the worst goddamn things ever recorded, let alone if you standardize for the cost spent to make it. I can't fathom why anyone would find it sexy, and even if you do I'm pretty sure you could easily find a ton of videos on Youtube that are both objectively hotter in the same way, while getting rid of the shitty other parts of the video as well as the music that just makes you wish an anaconda had suffocated anyone involved with the making of said "music".
Also, OP, uh, by new trend you mean an old one? I think just about every female pop singer has a song specifically about her ass/body parts. Taylor Swift probably has one although because she's targeted at 12 year old girls I'm guessing she refers to it as her fanny.
I like Iggy Azalea. Bounce, Black Widow, and Fancy. But the only videos so far I like of hers are the ones for Bounce and Black Widow. Most pop/hip-hop music videos are oversexed or otherwise just bizarre. I don't listen to music for the visuals (not that I don't enjoy well-produced videos) or who the musicians as people.
Bounce:
http://www.youtube.com/watch?v=cI1A405jBqg
I never liked Nicki Minaj, though "Pills N Potions" was a step up from her previous stuff. I don't like the voices she does, it's annoying. Iggy Azalea is a decent rapper, but not spectacular. Her stuff is fun - obviously I'm not putting it in the same category as other, more highbrow music, but just fun to listen to.
Sorry but both of those videos are terrible. As in, just lighting the amount of money spent making them on fire would be better in every way. Bounce is almost exactly what you expect to get from a white Australian female rapper making a Bollywood style video (which is to say surprisingly tame and lame, effectively her just in the Indian dress with the Bindi) and the other is an atrociously shitty homage to a hugely overrated Tarantino movie(s). I can almost imagine the brainstorming process: she watches that one Lady Gaga video and goes, hey let's do those shitty skits, random cameos, and rip off other Tarantino stuff!