Samsung Galaxy Note 4 was released several months ago and it seems it's a phablet that is placed too far away beyond most expectations of fans, even of critics... So, it's just a matter of time since almost all people will start questioning themselves about the future specs of next version of this smartphone.
It's useless to start speculating the Samsung Galaxy Note 5 specs while Galaxy S6 will not be released, but we can build a specs wishlist based on most technology innovations related to CPU, GPU, RAM, storage, card slot, photo/video camera, communication standards, display, etc.
So, Note 4 already has a Snapdragon 805 CPU, and it's expected (september, 2015) to get at least a Snapdragon 808 CPU (with Adreno 418 GPU) in order to keep a stable and not overheated gadget. To keep the trend of its main competitors it's possible for Note 5 to get the 810 version from Qualcomm, but with the same problems related to that CPU... Also, the most probable Note 5 will have 4GB of RAM.
It's display will be about the same size (or maybe with 0.1 to 0.3 more inches), a new technology needs to be implemented for better performances in the field of "colors"; it might be for the first time when Samsung will bring to markets a smartphone that will includes a smartphone with 128GB internal memory storage version (so we could have 3 versions: 32GB/64GB/128GB); it's not expected an improvement for the card slot in order to upgrade the memory storage with 256GB microSD memory cards; primary camera will increase between 3Mpx to 5Mpx and the secondary camera up to 5Mpx (here are expected innovations in video performances to increase the number of frames per seconds - 256fps? - it's less probable). Also, a bigger battery will be required and that means a bigger weight for next Samsung Galaxy Note 5...
Some publications speculated a compatibility with 5G communication standard, but I think it's 99% impossible because this standard is expected to be implemented around of 2020.
