I don't think I underestimate Ealham. A very good all-round player who I feel might actually have had more of a shot at Test cricket.
But I felt that Harvey had something exceptional about him. I have to admit that it does seem as though I'm in the minority here and that may well be just one of those things: that when I've watched him he's always tended to make runs and take wickets. That's made more likely by the fact that I've only really watched him in English cricket where he had such a massive influence on the great Gloucs one day team (so much greater than the sum of its bits-and-pieces parts) a few years back.
There's no doubt that Harvey did indeed have something exceptional about him. He wasn't called "freak" for no reason. He could do stuff precious few cricketers can do - he could turn a game with bat or ball in barely half an hour. He could also do near-useless but still incredibly impressive things, like drop the ball in his run-up, pick it up and just keep running in and still bowl exactly the ball he was aiming to bowl.
However, as I say, the Harvey package included some extraordinary natural batting and bowling (and fielding, too) ability and also a natural low threshold of boredom. Unfortunately, players come as a package - virtually every cricketer has bits that you'd like to keep and bits you'd like to get rid of. Botham and his extraordinary natural batting, bowling and catching talents, but also his natural aversion to the monotony of practice, is another example.
I sometimes think people put too much emphasis on basic talent and say "well if he'd not had this-and-that that held him back he'd have been a World-beater". You're not - entirely - doing this here, because as you say his influence in English domestic cricket was far greater, and obviously far more heralded because of the fact that the rest of his team also contained plenty of excellence (as a sum if not always as individuals - Mike Smith was the only other standout performer whose figures were consistently excellent) and thus won a hell of a lot of trophies. Harvey's bowling figures in England between 1999 and 2003 were indeed superlative, and his batting ones decent for an all-rounder. But for most of his career, he was never able to match that. And you know what? I don't think he's terribly bothered about that, because to him cricket was just a game. There were more important things, I think, than straining every sinew to do as well as he could every game he played.