Thanks! The Mini is still my go to - just the right balance of size and productivity
I can share my perspective on the size part (obviously this is very subjective):

a) The iPad Air is too big to carry around in addition to a laptop (see note on replacing laptops below)
b) The iPhone 6+ is too small to power type even with a BT keyboard
c) The iPad mini is still just about the right balance between size and productivity as far as a supplement to to the laptop goes

On laptops being replaced by tablets:

a) I find iOS in general to be too restrictive (so far) as an OS for power users (anything beyond writing emails, making power points, editing docs). If however, your primary need is emails and _light_ editing of documents, then I think one could easily not take a laptop today whilst traveling

b) I honestly believe tablets need to get a trackpad (or mouse) for real power use. Its not convenient to keep lifting your hands repeatedly - it slows down the process for power users and also hurts after you do it for a prolonged time

c) I do think the latest version of Surface Pro 3 comes pretty close to being a full fledged replacement for a laptop (not sure what it does for the trackpad part though - I've just read the specs, never used it)