Personally speaking, the RAM issue is a bigger deal with the iPad than the iPhone. I don't keep many tabs open on my mobile phone. Usually at most 2. Whereas with my iPad I will sometimes have 5 or 6 tabs open, and that's a serious problem with every iPad except the iPad Air 2 which has 2 GB of RAM.
So while I'd happily welcome 2 GB of RAM in the next iPhone, I think the bigger issue is that it's not featured in the iPad Mini 3.
Only problem with that is the impending multi-tasking that Apple will bring to iOS soon. This will undoubtedly require more memory and they equipped the Air 2 to handle it...the iPhone 6 & 6+ kind of got left in the dust since Apple boosted their screen size but crippled their ability to effectively handle multi-tasking with paltry RAM.