Why don't you test out a brand new Tamron SP 15-30. The latest new fresh batch should have a firmware that is compatible to a 5dmk4 and 80D if you ever get those bodies in the future. BAD thing about this lens is that it is NOT compatible with the USB Tammy hub so you cannot update the firmware at home.
I will say I used on of those boat anchor Tammy zooms and I loved it!!! It's a step above the Canon 16-35 f/2.8mk2 an pretty darn close to a 16-35 f/2.8mk3. I'm mentioning this because the f/2.8 is 1 stop faster than the f/4 zooms your looking at.
I like how that tammy performed with direct sun entering the lens. The 16-35 f/4IS with my 5d3 couldn't autofocus reliably when I shot that way with my camera.
These photos were nothing ground breaking but I really enjoyed how the Tammy rendered both in colour and easily on par with the 16-35 f/4IS in sharpness and micro contrast.