I was in a similar position about 4 years ago except I had the EOS3. As you have seen, the difference in size and weight can be substantial but of course so are the features.
BTW, there are quite a few differences in the choices presented to you and I agree with the recommendation that you keep what you have while you explore the differences until you find the right fit!
I know I did . . . mostly . . .
Larger version -> Cameras by Name