Most EF lenses take a tremendous hit downwards, in their sharpness, when they're mounted onto an APS-C body.
I'm using DXO's measured test results, as my basis of information, and they are accurate, in this regard.

For instance, I have a Canon EF 70-200 f/4 L that's rated at: 27 overall, and 24 for sharpness, when rated on a full frame Canon 5DS R. This same lens is rated at an overall: 23 and 18 for it's sharpness on a Canon 5D MK III.
Yet, when that SAME, EF lens, is mounted onto a Canon EOS Rebel (550D) T2i, it yields an overall rating of
only: 14 overall, and a sharpness rating of 9!

And that is, the highest, of the crop sensor, Canon camera's, also.

There is a very significant drop, in that Canon EF lens's overall, level of performance, which is, the combined ratings of all of it's individual test's for Sharpness, Chromatic Aberration, T-stop (light transmission), Distortion, and Vignetting have been combined.

Also, specifically, it's Sharpness rating has gone far down compared to when it was mounted on the full frame camera that it has been designed to be used with.

This is why I personally cringe, when I read certain people, posting to new comers, that they should purchase, all full frame lenses for their new ASP-C crop sensor camera's; as those camera's, are designed to used with, "DX" and
EF-S" lenses, to get the maximum performance, out of them!

It's nonsensical for a brand new photographer, who has just purchased his first (ASP-C) crop senor camera body, to set out purchasing, full frame DX and EF lens, for it, (except in certain very specific, cases,) JUST BECAUSE, he may, SOME DAY, be purchasing, a full frame camera!

It is critical to place the correct type of lenses, onto the type of camera, that you presently own.

In the vast majority of time, you will LOSE much sharpness, by placing a full frame lens, onto a crop sensor body.

There was a man who did this with a, (I believe) 24-70 f/2.8, onto a full frame camera, perhaps, it may have been, a
Canon 7D or 7D MK II, and he actually reduced his effective M-Pixels down to something like 8!

He sent the camera and lens in to be serviced, and they came back fine.

Finally, someone else figured out, just what was going on!

That full frame lens itself, mounted on a full frame camera, would have yielded 24 M-Pixels, yet, only 8, on his crop sensor body!

This is something that you can, and should, check out, on www.dxomark.com

Your lenses, and what body, that you are using them on, to determine their actual effective sharpness, and performance.

Yet, you will almost always do better, with a crop sensor lens, on a crop sensor body.

Most EF lenses take a tremendous hit downwards, in their sharpness, when they're mounted onto an APS-C body.
I'm using DXO's measured test results, as my basis of information, and they are accurate, in this regard.

For instance, I have a Canon EF 70-200 f/4 L that's rated at: 27 overall, and 24 for sharpness, when rated on a full frame Canon 5DS R. This same lens is rated at an overall: 23 and 18 for it's sharpness on a Canon 5D MK III.
Yet, when that SAME, EF lens, is mounted onto a Canon EOS Rebel (550D) T2i, it yields an overall rating of
only: 14 overall, and a sharpness rating of 9!

And that is, the highest, of the crop sensor, Canon camera's, also.

There is a very significant drop, in that Canon EF lens's overall, level of performance, which is, the combined ratings of all of it's individual test's for Sharpness, Chromatic Aberration, T-stop (light transmission), Distortion, and Vignetting have been combined.

Also, specifically, it's Sharpness rating has gone far down compared to when it was mounted on the full frame camera that it has been designed to be used with.

This is why I personally cringe, when I read certain people, posting to new comers, that they should purchase, all full frame lenses for their new ASP-C crop sensor camera's; as those camera's, are designed to used with, "DX" and
EF-S" lenses, to get the maximum performance, out of them!

It's nonsensical for a brand new photographer, who has just purchased his first (ASP-C) crop senor camera body, to set out purchasing, full frame DX and EF lens, for it, (except in certain very specific, cases,) JUST BECAUSE, he may, SOME DAY, be purchasing, a full frame camera!

It is critical to place the correct type of lenses, onto the type of camera, that you presently own.

In the vast majority of time, you will LOSE much sharpness, by placing a full frame lens, onto a crop sensor body.

There was a man who did this with a, (I believe) 24-70 f/2.8, onto a full frame camera, perhaps, it may have been, a
Canon 7D or 7D MK II, and he actually reduced his effective M-Pixels down to something like 8!

He sent the camera and lens in to be serviced, and they came back fine.

Finally, someone else figured out, just what was going on!

That full frame lens itself, mounted on a full frame camera, would have yielded 24 M-Pixels, yet, only 8, on his crop sensor body!

This is something that you can, and should, check out, on www.dxomark.com

Your lenses, and what body, that you are using them on, to determine their actual effective sharpness, and performance.

Yet, you will almost always do better, with a crop sensor lens, on a crop sensor body.

I totally understand what you want. I too have a 7D and 7D mII, and I carry a sony RX100 in my purse - BUT there are days I just want a lighter DSLR. I love using a DSLR - and the 7D's are back breaking for family days. I tried the SL1 and didn't care for it. That camera is so little that the lenses felt off balance and it was very slow. So I also have decided to buy T6i but I'm forcing myself to sell off several of my Point and Shoots first (I have 6 of them). The 80 D is awesome but still too heavy for what I want.
I think having 1 pro type camera and 1 Rebel is a great idea -- go for it! I wouldn't wait for the T7i, I bet that is several years out.