I think because it hasn't been updated recently enough. For some crazy reason the author prefers WOWUI, and there's a new version up there that I refuse to download because it seems like I get trojans every time I download an addon from that site. I'm waiting until he updates it on his Google Code site or on Curse.
I also arrived at tomquest2 without the assistance of this thread.. That will show me!11 I should have just came here and seen what investigation you guys had already done, than crawl through wowui, discovering that questguru is changing pretty dramatically, and than crawling through WOWI and Curse looking for a replacement.
Tomquest2 seems nice.. I like the idea they have about alt right-click on a quest setting a key bind to that quest's quest use item.
Overall, I'll miss the history portion, but Tomquest2 imo is great..