For those interested, what I did when I proposed this list was make a "score sheet" up for a number of potential candidate tanks. I (yes, yes, it is somewhat subjective but, it is better than the SWAGPOOYA method) rated each vehicle on a scale of 1 to 9 for firepower (f), mobility(m), armor(a), reliability(r), fighting efficency(e), and its impact on the war(i). I did this twice. The first time I simply assigned a number I felt was correct for the vehicle in that category. I then went back and "smoothed" these to average a value of 5 for the entire category. This gave each category more of a standard curve shape.

The scores I ended up with were:

M3 Stuart 36
M4 Sherman 42
T34 40
Pz III 38
Pz IV 38
Pz V 38
Pz VI 38
Matilda II 30
Crusader 26
Churchill 37
M3 Lee / Grant 36
IS II 36
Valentine 29
KV series 25
Pz 38t 30
Souma 35 21

So, I did try to include some weighting for vehicles like the Matilda whose service in the limelight was rather short lived. And, each category was assigned on the basis of what would have been the vehicle's capability when it was operated versus opponets of the period rather than for the war as a whole. It was just many of the earlier British tanks were too unreliable, lacked firepower (the 2pdr having no HE round hurt and the gun itself was obsolesent by 1941), and had cramped crew positions and other associated problems (like having to relay the gun after each shot due to it having a shoulder aimed in fine traverse system using a friction brake for example).
This way I tried to make sense of the whole idea boiling it down into a list of just 10 tanks.

__________________
Truth is stranger than bullshit!