I did disagree with your original post, but I think there are some valid points in here.
Ovett wasn't near Coe at 800m in terms of ability to run a fast time. He was a very good runner the kind of race the Olympics turned out to be. Somewhat reminds me of what Coe said about Tom McKean, who wasn't super quick, whom Coe described as "very dangerous in a 1:45 type race).
There wasn't much between Ovett and Coe on time over 1500m/mile (obviously, as the flip-flopped the records several times). Ovett wasn't quite the same after the fall on the railings (which happened before the world-record 1500m at Rieti). He did get very fit for the next Olympics, but then suffered the breathing/heart problem, which subsequently prevented him training with the intensity needed for peak 1500m performance. It's hard to believe that without those problems he would have run at least as a past his peak, 30-year-old Coe did.
I was actually there when Ovett defeated Rono over 2 miles and he was traveling with ease throughout, comfortably covering Rono's surges. Given some of his performances in longer events that were either for fun or training (fastest long leg on the Southern Road Relay at least once; 65 min half-marathon win over British Marathon Champion as a training run; win in the Inter-Counties X-Country at 7 1/2 miles; good runs in the National X-Country Championship at 9 miles), it's at least conceivable that he would have been as good if not better at 3000m than 1500m.
His 5000m potential is tantalizing. He never seriously tried it before he he had the fall and the breathing/cardio problems. Never ran really quickly, but Harry Wilson (coach) thought he was in world record shape at one point in 1987. He did beat Mark Nenow in Dublin, and Jack Buckner and TIm Hutchings (first and fourth in European Championship 5000m later that year) very comfortably in the Commonwealth.