Remember that you don't have to use the Sense launcher, in which case you also don't have Blinkfeed.
Given how new the phone is there are a few ROMs available already (all Sense based so far), and I'd be surprised if there isn't a lot more development. And while there’s no S-Off so far, you can do a lot without (I've read here that it is slightly less restrictive than last year's models).
It's too early to really say, but I'd not be too quick to write it off. Be interesting to see the first AOSP ROM (there's a pre-alpha CM thread in the ATT One thread at XDA, but I've not read very far).
XDA have really fragmented their One forums though: separate forums for each device version, and then separate "development" and "original development" forums for each. I don't see that last as needed, but it seems to be what they do these days.