In 2005, Flintoff seemed to be constantly threatening with the ball. Flintoff is one of the great wasted talents. Should have averaged 40+ with the bat and sub 25 with the ball given the talent he had. He is still in that rare club of genuine opening bowlers who could bat in the top 6, but if he'd capitalised on his batting and bowling talent a bit more his legacy would be so immense.
In the earlier days, he didn't seem to take his bowling seriously enough. Even later on he was quoted as saying "I'm a batsman who bowls". It was about 03/04 when the cricketing world started saying "hang-on, it's the other way around".
40+ with the bat would be over-optimistic. Flintoff had surprising timing, great power, and was orthodox-looking enough to figure at 6 when in form. But he was also fragile in the Michael Vaughan sense of
any delivery delivered by any player on earth can get me out kind of batsman. In form, he'd average 40 over a spell and look very good but still occasionally a bit crazy, for the rest of the time he'd average and look like ...well ... a bowler who bats ...and average about 23. It's with a heavy heart that I say his overall batting average of 32-ish about reflects his talent with that particular block of wood.
His bowling on the other hand could have been better. And to answer this thread's question, he was definitely one of the more talented upwards-of-30 averaging bowlers. When he finally started taking bowling seriously at Test level, and remained injury-free, he averaged about 27-28 with the ball, which isn't bad in this era.
So in my opinion, if Flintoff had his head screwed on all his career, and had a bit more luck re: injuries. He'd have a Botham-like career average of Bat -33 and Ball - 28, but didn't quite get there.
Terrific player though, and the country is all the better for his influence