I think you'd better do a little math, and read some stats, before you proffer "solutions," Shadow.
The 5Ds + 200-400 would raise my cost to $14,500, and it still would give me inferior results (1x4 on or off) to a D810 + 300mm. (And that is rated at the 200-400's best focal length, 300mm, not at its worst.)
So now your argument basically comes down to, 'It's cheaper.'
The 5Ds gives you more pixels on target than the D810, with similar AF performance. You're shooting wildlife and macro, so that's what you want, isn't it? After all, isn't that why you chose the D500 over the D5 - more pixels on target?
No, SenScore does give their methodology. Try reading the links (I'd recommend you start with the FAQ and About).
I've read the whole website. They haven't given their method at all. All they've said is what's on their test bench and that (for sensors) all the numbers are relative to the performance of the D800.
No information whatsoever about how they actually measured it, what values they measured, what the raw measurements were and how the raw measurements were used to calculate a final score for each aspect of performance measured. It's the same reason DxOMark's overall score is also useless - there's no information as to how it's derived. Unlike Senscore/Lenscore, however, DxOMark publish the actual measured data, which is what anyone with any technical knowledge actually argues on. Ever noticed how no-one ever argues 'Sensor A scored 96 on DxOmark and Sensor B only scored 87, so Sensor A is better', but rather 'Sensor A had 14.3 stops of DR at ISO 100 and decreases linearly with increasing ISO, while Sensor B is equal at ISO 800 and above, but plateaus below that, suggesting a greater degree of read noise'? That's because they're using actual measured values and simple derivations thereof (e.g. log conversions and reciprocals), not silly 'benchmark scores' derived via hidden, arbitrary weighting scales based on the tester's preferences.
It's as irrelevant an answer as if you asked a scientist how they got their results and arrived at their conclusion in an experiment, and they told you, 'I used this brand of test-tubes and this thermometer, and my lab bench is made from stainless steel', without actually telling you what they did to get their data, and how the data led to their analysis.
And BTW, I just gave you a link above to a DxO verification of the 300mm's superiority to the 200-400, since you don't like SenScore.
You're the first person I've ever seen give any credence whatsoever to DxO's lens scores. Unlike their sensor measurements, where the raw data is published, their lens scores are just derived values.
Just like Lenscore's ratings, DxO doesn't actually say what 'perceptual Mpix' actually is, let alone how it's derived. They're just expecting you to believe a derived value (not a simple measurement like lp/mm) at face value without saying how it was derived from the raw measurement, or, indeed, what they actually measured.
Try a site like Photozone - which actually gives you the raw, measured values at each focal length and aperture combination, at middle, edge and corner - or a site like Digital Picture, which lays out the test chart in front of you so you can see for yourself how the sharpness and CA look.
A 300mm has better stats than the 200-400 at its best, far better at the 200-400's worst, and is half the price.
See for yourself. 200-400 at 560mm/5.6, 300 with 2x TC at 600/5.6. The Canon on 21MP, Nikon on 24MP, so similar magnification.
The D810 has far better stats than the 5DSr on DxO also.
Obviously. What it doesn't have is pixel density.
You said it yourself - you chose the D500 over a full-frame option because it gives you extra reach with the same focal length. Reach is defined by pixel density - the denser your sensor, the more pixels you land on target. A 50MP full-frame sensor gives you 39% more pixels on target than a 36MP full-frame sensor, and 11% more pixels on target than a 1.5x crop 20MP sensor.
Also, the sensor is only better at base ISO. At ISO 800 and higher, DR/SNR is
more or less identical between the D810 and 5Ds. Besides, if you're using it as a dedicated wildlife/macro camera (as opposed to shooting landscapes), shooting insects at base ISO, either in good light or with flash, how much DR do you need anyway? If the scene only has 8 stops of DR anyway, it makes no difference whether the camera is capable of 11 stops or 14 stops - you'll still capture all the information. And, at ISO 800 and up for moving wildlife or at dawn/dusk, there's no difference in noise/DR performance between the two sensors.
The D500 has far better stats than the Canon 7D II on DxO as well.
It also gets you fewer pixels on target.
Not suggesting that the D500 and 7D2 are remotely equal cameras - one's a brand-new, pro-level camera with an APS-C sensor, the other's a two-year-old prosumer body.
This thread isn't about what you use; I created a thread about what I use--and why.
You use neither the D5 nor the 1Dx2.
You admit you haven't used Canon for landscapes, because there are better options, so you halfway agree.
(In fact, on another thread, you said if you could only have 1 camera it would be the D810.)
Point is, I don't have to have one camera. So I use the best one for landscapes and other things that don't move - the A7r2, producing stitched panoramas whenever subject movement and lighting let me get away with it (which is often) - and the best ones for wildlife (big animals, I don't tend to notice little critters) - 1Dx or 5Ds with 200-400L.
What hasn't seemed to dawn on you is that, for action, Nikon also provides a better solution across the board also (better AF, better stats, across the board).
Where does this 'better AF' thing come from? The 1Dx and D4 performed more-or-less identically. There have been no formal head-to-head AF tests between production models of the 1Dx2 and D5. Both of them did fine in tracking a manoeuvring drone flying erratically while weaving in and out of trees and power lines. I have no doubt neither will have any trouble tracking a lion running through long grass and pouncing on an impala.
And Nikon's 200-400 is woeful compared to Canon's. If you're talking action, things move. Unless you're permanently constrained by maximum focal length, you're zooming in and out constantly for the best composition. An animal could be at the 560mm end at the start of a run, but have you at the 200mm end and reaching for the backup camera with 70-200 attached by the other end of the run. Relying on long primes alone is hardly a solution if you're shooting large animals coming up close.
DxO and SenScore both place the Nikon cameras higher than their Canon equivalents, pretty much across the board.
The new 1Dx II is the only Canon camera to get an equal placement with its Nikon equivalent on DxO ... though it does not on SenScore.
The 5DSr is lower than the D810 on both, the 7D II is lower than the D500 on both (it will be on SenScore when it comes out, watch).
I don't care about across-the-board or derived scores - only scores in the areas that are relevant to a particular application, and only raw measurements or simple transformations of raw measurements.
For nonmoving subjects, I use the A7r2 because it has the second-highest DR and second-highest resolution at base ISO, while having the best lens selection of any full-frame camera out there (also, it fits easily on a drone). I don't care how it performs at high ISO or that its AF is mediocre with non-Sony lenses, since I'm not using it for that.
For wildlife shooting, I use the 1Dx because, unlike the D4 and D4s, it can hold a Canon 200-400L. The two extra megapixels are also nice, but hardly game-changing. I don't care that it underperforms at base ISO, because I'd rarely be shooting it at ISO 100 and, at typical dawn/dusk wildlife ISOs, sensor performance is the same. As a second body on a game shoot, I like the 5Ds because it gets me heaps of pixels on target for those long-distance, focal-length-limited shots. Again, I don't care that it underperforms at base ISO, because I'm not shooting it at base ISO.
Overall scores are basically useless because they don't tell you anything about a camera's performance at any particular role. A camera that's above-average in everything, but not exceptional at anything, would probably top the overall scores, but you wouldn't select it for any given role (other than maybe giving it to a beginner who doesn't really have a shooting preference), since it's not the best (or even top three) for that role. It just happens to be reasonable at everything.
