To the OP of this thread - several comments.
First I have a 70D. it's my main APS-C camera (backups = 40D & SL1). With the exception of some AF surprises (I've reverted to center point AF & AE shooting w/ap>2.8) - IMHO, the 70D is a solid camera. While initially skeptical, at least, I really like the touch screen. It's easy, intuitive, and fast. And it works.
The more I use the newer STM lenses, the more I like them. The 18-135mm is probably a great single-lens solution. Now that I have multiple APS-C bodies (I just recently added the backups), I tend to pair the 18-55mm STM (great MFD & IQ, a real sleeper of a lens - a real surprise, again!) with it's complimentary sibling, the 55-250mm STM. Again, nice IQ, light weight, very affordable optics. I hear the 18-135 may be marginally sharper - not that sharpness is all that (sorry for the potential heresy).
The kit lens purchased with my original 60D was the oft-maligned EF-S 18-200mm "all in one." Needless to say, the 60D is long gone - off to college, and the kit lens (above) still remains - mounted today on the 70D or its backups. In fact (more heresy) I just this week added the Tamron 16-300mm VC PZD and Canon's newly released 50mm f1.8 STM (as an upgrade to my 50mm f1.8 Mk I). the later is a nice mid-range portrait lens on an APS-C sensor camera.
If the best lens is the lens on the camera you have with you, applying that theory, you may wish to consider either of the above all in ones. While I now have 38 lenses available for daily use (when they are not out on loan?), rarely a day goes by when the 18-200 or now, maybe the 16-300 is not used. earlier today, I documented a construction project at home with the 70D & the new tamron. such lenses, even if not as tack sharp as - say - the 24-105L or the 17-40L or any prime lens of your choosing - provide compositional flexibility - unequaled except, perhaps, with my old "paparazi" lens - the 35-350mm L (which really requires a monopod/tripod - as there is no IS - to channel my inner WJC).
Other faves on the crop bodies are - again stm glass - the 24 (ef-s) and 40 (ef) pancakes. sweet, cheap, light - almost comically, nice contrast, good color saturation - what's not too like? I cannot speak about the new 50mm stm (not a pancake) as it has just arrived & I've only a handful of shots with it to date.
When circumstances permit, another favorite - for wonderful IQ - is the 70-200m L IS - I use the f4 - as I don't relish the size/cost of the f2.8. This is such a sweet lens, I don't think you can possibly go wrong with this lens. Some days when I find myself a bit flat creatively, I'll take this lens and just shoot minutia - sometimes just chasing light and shadows. I really enjoy this particular lens. Can't quite describe it.
At the short end, on an APS-C, it's a focal length equivalent of 112mm - which I find to be a very comfortable upper body portrait lens - or tighter, moving away from the shortest FL. I've also enjoyed decent results using the long end for close-up work (not true macro shots).
Anyhow, I think the 70D plus good glass probably adds more to your capabilities than the pricier 7D2. Again, even if you discount its solid video abilities, the 70D is a good still camera - by any standard.
I'd encourage you to not automatically equate sharpness to good glass. When considering any lens, my first issue is - does this lens extend my present capabilities? if not, than why? sharp is good, except when it's not good.