What keeps Hardy from being a great novelist?

As noted in yesterday's post, Thomas Hardy is a sucker for those Victorian coincidences, and though this is not the undoing of "Tess of the D'Urbervilles" it doesn't help - Tess, who has to work in a rugged and poor turnip farm to survive after her husband, Angel, debarks for Brazil, wanders across the countryside hoping to ask Angel's parents, whom she has never met, for help and advice (Hardy makes clear that they would have helped her), but amazingly (!) she overhears a conversation between Angel's two brothers and the prim woman whom he might have married - and this dissuades her. You figure the chances. Then, trudging back to the farm, she stops in a village and overheard a sermon being preached by none other than Alec D'Urberville, who had seduced her and fathered her child - but now he is reformed, having been saved by none other than Angel's father. Huh? This kind of crazy plot mechanics keeps Hardy from being a great novelist - though he's a damn good one and great at certain things: the interaction of character with landscape, for example. The whole episode of Tess's 15-mile trudge across the countryside, mountain paths, open fields, villages, her tiredness, her poverty, her desperation, is conveyed so beautifully - if only he weren't such a slave to plot. Readers like plot, however - all of us - and it's still interesting to see how he will work out the kinks in this plot twist. Is Alec really reformed? Seems dubious to me. Will Tess want anything to do with him? I would hope not. But what options does she have? She is not a modern woman - she is still a woman of her time, limited by the scope of her family, upbringing, and environment - that's part of the tragedy that Hardy so truthfully brings to light.