The problem is that people whine whenever there's something just a tad challenging. Remember when they introduced Grineer Manic for the first time? His laugh would actually make you tense up and prepare to face him, but now? He's no more than a laughing joke.
What is wrong with content that's only clearable by a certain portion of the player base? You wouldn't expect a level 10 Paladin to clear a level 999 raid dungeon in other MMORPG would you? So why is it different when it comes to Warframe? We're not even asking for content that's equivalent to Dark Souls difficulty.
People forget that they have their own limit. The game is already easy as it is, if they can't get past rotation A then accept that they're bad and move on instead of asking for nerfs to suit their skill level.