+5% modifier means +0 when there's not a 20 or more research base value. USUALLY, there isn't yet a base of 20 research to benefit from the +5% that the first civic change can offer. However, down Nomadic Lifestyle you get access to Wanderers and if you avoid popping the first goodie huts you find and wait for a Wanderer to do it, you are assured of those first huts NOT being negative results. By going for NL first, you can do this safely knowing that no other opponent will be able to field anything to steal those huts off of you. The huts may be able to get you technology faster than a +research% that you aren't immediately going to get any benefit out of for a while. (And even if it's been changed to +10% then it's still likely the huts will get you the tech faster than +1 per round.)
I would have to say that in most of my games, if I start anywhere near any other AI, they are very likely to pop all the goody huts before I ever get even one wanderer out, due to their multiple free units. (Emperor or Immortal, diety puts the AI too far ahead for me to enjoy it.) On top of that, my wanderers need to survive the potentially dangerous wildlife (not guaranteed even standing on a forested hill, although dangerous wildlife might not yet have spawned in the first, say, 30 turns) and the hut must not be defended by a barb unit (also somewhat unlikely this early, but possible).
At most I might get one or two nearby goody huts that I discovered with the initial (split) stone throwers, whereas others are too close to the AI and are claimed by them (or else popped by my throwers to deny them from the AI). Usually this also requires I have a high-hammer start, otherwise I'm still building e.g. klasie caves by the time Nomadic is complete.
That said, as you say, the potential of a good reward from a hut is probably still better than a civic change that doesn't benefit you at all since your tech per turn isn't high enough to round up (and even partial research progress could be worth dozens of turns saved vs. just a +1). I do tend to go for Nomadic first anyway simply because it gives me something to do after I've built the early buildings so I'm not just spamming brutes (which idle and just cost maintenance) or leaving the city idle (wealth production being not yet available); I hadn't analyzed it as closely as you have. I might even get Gathering before I go for Language - it could reveal a good commerce resource to work. Probably the only way I might get Language first is if I settled near a natural wonder.