I absolutely hated Mark Harrisons original bloodletters, the ones that looked like dancing dogs back in 3rd - 4th Ed. I despised his space wolf scouts, they were bloody terrible.
Now some of my favourite models are being sculpted by him, and he does fantastic work in plastic.
Everyone can learn, improve and fix past mistakes. Yes, some of his previous work sucked. I too had to put up with sub-par codeces. However, given the nature of gamers and the internet, don't you think he's had plenty of incentive to learn from his team-mates like Phil, and maybe improve? There have been substancial changes in Games Dev, don't you think those might have had an impact, like the whole team having a hand in pretty much every book? I do hate it when people see a few bad initial works, and assume they will be shit forever. I was a crap painter once...
He's not a crap writer. Some things seem at least a little creative from him. But his blatant disregard for balance. My god. He managed to write both the worst (Nids) and the most overpowered (Guard) codex in just one year of releases. That kind of inconsistency takes a long time to iron out. And sure, some day I could forgive, but it is still way too fresh in memory and the stink still lingers.