I really hated how forced Dave's "wow so cool"ness was at first, but really it's everyone's pesterlogs that make me grow to love them. Without the pesterlogs I would still think Dave was a prick, still be unable to look beyond Jade's Mary-Sueism, and continue to forget why I like Rose. Andrew's speed-running through the troll introductions has allowed us to get to know them a lot faster and not dealt with all that "olololo Dave fiddles with his stupid captchalogue modus for a week" stuff, which has make first impressions somewhat short-lived. Hell, I think I almost stopped reading Homestuck in Dave's intro week.
And I don't feel that Andrew's necessarily a very good storywriter as his M.O. for that is largely just symbolism-riffing and making something cool out of something initially not very captivating at all. Nor do I think he's necessarily that good at crafting characters as they really feel a lot like how grade fives write characters in their english classes (write a paragraph with five things your character likes, that is your character's personality!) but it's the pesterlogs that really shine. He's a really good dialogue writer, throwing in humour and brief glimpses at underlying personalities in conversations, which is what good writing is. Really, without the minute interactions that the pesterlogs bring, I don't know how much I'd actually enjoy Homestuck. Without the logs, they're just Problem Sleuth-type characters, unable to really be characterized past what the narrator can surreptitiously imply, and where PS was all-silly, HS is taking its story seriously, so I don't think that'd work out.