Who says the Wellington was "the best"?? It was terrible! It and other early RAF bombers forced the RAF to develop better aircraft, indirectly leading to the Lancaster.
We're not saying the Wellington is a better choice because it's better. We're saying it is because it was used more, it was much more representative of the Bomber Command, and it's more recognizable.
Fact of the matter is any early RAF bomber's going to suck horribly. Doesn't mean we don't want any!

It just means we want the right ones. If you only got to put in one early war naval dive bomber for the US Navy, would you pick the SBC-4 Helldiver, or the SB2C? One was obsolete as the war started, was weak, slow, underpowered, couldn't carry anything. The other was a very common and representative craft, and yet still rather slow, underpowered, and couldn't carry anything

Chances are of the two, the SB2C is a better choice.
Same with the Whitley vs the Wellington. Both were there. The Wellington's a better choice to include in AH, though. I applaud you for looking for early war aircraft to fill the holes, however. So many holes...