A jumbo would be a worse easy eight, being better only in having slightly better armor, the easy eight was the last evolution of the sherman tank, a jumbo in the game would be a slightly worse KV1.
How many times do I have to say this? The "E" meant "Experimental", it was not a linear progression of models. The E8 was also not "the last evolution of the sherman tank", there were many post-war variants made by other countries, most notably (imo) the Israeli M-50 and M-51 Shermans. Finally, the KV-1 was made in 1939 and could be penetrated frontally by the Panzer IV KwK 40, the M4A3E2 was made in 1944 and could not be frontally penetrated by the Tiger I KwK 36 except at point-blank range. Comparing both tanks defense to the Tiger I, the Jumbo is clearly superior.