OP didn't mention low light/high ISO as a concern, but since it's on the table, let's talk about it.

I shot for five years with a pair of original 7D.... same 18MP as OP's 60D, though her camera is slightly newer and got some tweaks. The highest ISO I'd use with it was 6400. And with those cameras whenever I used 3200 or 6400 I knew it would mean more post-processing work to make images usable.

Now shooting with a pair of 7DII, I use 3200 and 6400 freely... little to no concern. In fact, I use 8000, 12800 and even 16000 at times... usually with some add'l post-processing. Now, I have no doubt that the much newer 5DIV is even higher ISO capable... and the 6DII may be about the same (some say it's not much better than original 6D, but that camera was widely regarded as one of the best high ISO models in it's day).

But neither 7DII's nor 80D's high ISO is anything to sneeze at. 80D is capable of about same as 7DII high ISO... with 20% more resolution to boot.

Decide for yourself... Following is a test shot I did with 7DII at ISO 16000. It was shot RAW with care to avoid under-exposure, lighting was from single lamp with a 60 watt bulb about 10 feet away and indirectly from a small window about 8 feet away. Image was converted in Lightroom 6 with default levels of noise reduction and sharpening, a slight crop to 4:5 aspect ration and a little boost in contrast were the only adjustments done....



As you can see by pixel-peeping with the greatly enlarged detail on the right, there is some noise in the image. But IMO it's pretty well controlled. I'd have no problem making a quality 8x10 print from that image. I've made even larger prints from high ISO 7DII images by doing a little extra post-processing in Photoshop with a Noiseware plug-in.

I hardly think 7DII or 80D are limited to "good lighting". They're at least 1-1/3 to 2 stops "better" than the models they replaced. Heck, compared to another generation older 60D, it might even be more than that. Of course, recent full frame with less crowded sensors and larger individual sensor sites are even more high ISO capable. But I really think FF have seen a little less improvement compared to earlier FF models, than the current crop of APS-C have compared when to earlier APS-C.

You're probably already aware of it.... Shooting "in a gym", I'd also make a point of using the 7DII's new Anti-Flicker feature. Introduced on 7DII and avail. on many or most models since (incl. 80D, 6DII, 5DIV), that's proven to be really effective dealing with fluorescent, sodium vapor and similar types of lighting that were so notorious for causing a lot of exposure issues in earlier cameras. Anti-Flicker detects the cycling off those types of lighting and times the shutter release to coincide with the peak output of the lighting. Prior cameras without it, I had to take lots of extra shots because I knew the lighting would "fool" the camera and cause a lot of badly underexposed image. Now with Anti-Flicker enabled on my 7DIIs, I rarely see any problems. Works great! (Nikon has it on some models, too... I know for sure D500 and D850 have it. They call it "Flicker Free" and it's a little more complex. Canon's is simply off or on and it auto detects the cycle of the light. Nikon gives users choice of 50 Hz, 60 Hz or Auto settings. I hear it works similarly well, though.)