...But, but, but...
(Rumored) negligible design change from the 6/6s (third year in a row with the same design language!!). An even larger, more unsightly camera bump on the back. NO 3.5mm headphone jack!!! Antenna line bands STILL present - only slightly modified location of them being at the top and bottom of the phone...
....Those, and other (supposed) shortcomings = FAIL to some people on the internets...
Certainly, it's not my place to tell anyone else what they should, or shouldn't spend their hard earned money on, and if one feels that the rumored specs and features of Apple's 2016 iPhone aren't worth it to them as far as upgrading goes, so be it. But for myself, an upgraded A10 series processor, possibly a higher storage starting point (32Gb), or a higher end 256Gb storage option, improved camera module/optics, possibly the second generation version of 3D Touch, or (would be pleasantly surprised to see) a screen with features comparable to those of the 9.7 iPad Pro's, and possibly a smart connector option on the plus size version - are viable/compelling reasons for me to consider upgrading from my 6s Plus to what Apple introduces in September. Not saying that I will though, but I won't dismiss it out of hand right now before anything has been officially announced...