Glider
Captain
Let's compare historical data.
Vickers Wellington.
11,460 aircraft produced.
47,409 sorties flown by RAF Bomber Command. 4.1 sorties per bomber.
Avro Lancaster.
7,366 aircraft produced.
156,192 sorties flown by RAF Bomber Command. 21.2 sorties per bomber.
It appears to me the Lancaster was the level bomber of choice. The Wellington was used only because the Lancaster wasn't available during 1939.
Well no one will disagree with you on that score but as the Wellington was replaced by the Halifax and Lancaster you wouldn't expect anything else.
Its a bit like saying that the P40 was only used because the P51/P47 wasn't available during 1941/2