Hi Chrasmus (OP), I have D7000 and I have played with 5DM2, 5DM3, and 6D.
D7000 is a bit different than D5100 in that almost all major shooting settings are accessible by button on D7000, whereas D5100 requires going into the menu. I'm not sure about the detailed customization difference between D5100 and D7000.
Canon does lack EC in Manual mode. There are already threads on this topic. If you are a Nikon users who do use this feature with AutoISO, there is no workaround on Canon.
Comparing D7000 to Canons (5DM2, 5DM3, and 6D), D7000 is more customizable. Details below. It depends on individuals if they care about these customization. Customization helpful and is something users get used to. But I don't think it is deal breaker; it just take some time to adjust.
On D7000, Aperture and Shutter dial can be customized to either dial in all modes. In Manual, Av, and Tv modes, main dial and secondary dial can be customized to control Aperture or Shutter. On Canon, main dial controls Aperture in Av mode; main dial controls Shutter in Av. I don't see a way to swap between main control dial and quick control dial on Canon. For people who shoot using all 3 modes (M, Av, Tv) in different situations, they might prefer Nikon's customization. Users do not have to think about which mode their in. The same dials changes aperture and shutter in all 3 modes. For those who always shoot in 1 mode (whether Manual, Av, or Tv), then it doesn't matter.
On D7000, each dial direction and exposure meter direction can be flipped. So I can match the direction to turn the dial for Aperture, Shutter, and ISO to the direction indicated by the meter. Canon does have flip rotation function, but I cannot get all 3 controls to match the same direction as meter; unless I missed some function. Let's say the meter is set up with - (underexposure) to left and + (overexposure) to right. On Nikon, if I'm underexposed, I can make my aperture larger (smaller f number) by turning my dial to right, or decrease my shutter speed by turning my dial to the right, and increase my ISO by turning toward right. On Canon, at least one of A, S, or ISO is going the reversed direction as the exposure meter.
On D7000, Bracketing and WB Kelvin settings can be set using HW button. I am not sure whether D5100 has hardware button access for these 2 features. On Canon, need to go into menu. Can be a big factor for Kelvin shooter.