A bit of advice please on my upgrade thoughts:
I have a 400D, about 4 years old, and intend upgrading pretty soon. I was going to go for a 7D, but with the advent of the 70D think I will go for that instead. I take (or try to

mainly landscape, sailing and wildlife shots, but want to try some sport and macro soon. I don't take indoor or portrait shots, children, pets, etc.
The lenses I have are a Sigma 18-200 DC, EF 70-200 F4 L IS USM, 1.4x Extender and a Sigma 70-300 AP0 DC (which doesn't get used much, admittedly.)
Now, if I go for the 70D, I'm tempted by the 18-135 IS STM to give me the low end and to overlap with my 70-200. I guess an alternative (but more expensive choice) may be the Canon EF-S 15-85 IS USM.
The 18-135 is referred to as a kit lens and I know there is a feeling that these lenses are not-pukka - but judging from the shots on this thread, people seem very satisifed with the lens.
I'd appreciate any comments on my thoughts, or what I may be missing.