I think there's a danger of dismissing anyone who is more introverted or even more intellectual as being autistic or having Asperger's. Not everyone has to be super outgoing. Nor should it be the case that if you aren't, then suddenly there's something not quite right about you.
Even if you are socially awkward, that doesn't make you autistic either. It's not like there are only extroverts and then those with autism. That's how people started to come up with the idea of having an autistic Peter Parker as well for Homecoming, and thinking Asa Butterfield in X+Y was an accurate portrayal of him, just because Peter was more of a loner and was more shy during his high school years.
In all the classic FF comics, Reed was certainly genius level and thought more quickly than everyone else. But he never came across as if he were so socially awkward or unable to relate to people.
Did he lock himself away in his lab for long periods at a time and isolate himself? Sure. But so did Tony Stark, sometimes for weeks on end.
Reed still seemed confident and sure of himself socially and was a man of action and adventure. That's why I saw him more like Indiana Jones or Doc Savage rather than someone like the Professor on Gilligan's Island or Carl Sagan or John Nash (from a Beautiful Mind), or any other more nerdy type.
There are a number of things wrong with the concept:
1. It mischaracterizes autistic people.
An autistic person could have those characteristics, but they're not the key, defining characteristics of someone with autism. That description could just as easily be applied to someone who is a
sociopath. I have one nephew who is autistic and one who has Asperger's, and that description doesn't describe them
at all. Not even close.
Those are cherry-picked characteristics by a writer who is trying to force something they think is clever. They're not actually describing what autism is really like.
2. As you state, it falsely leads to the perception that anyone who is socially awkward or has social anxiety is on the spectrum and that isn't true and, again, is a misrepresentation of autism.
3. Reed is adventurous and not afraid to go out of his comfort zone. He only locks himself in the lab when the world is in peril and needs to really figure something out. Other times, he's pushing boundaries. It's not about "solitary interests" it's about things that will save the world, or, in calmer times, make the world a better place. Reed is a hero. Heroes don't pursue solitary interests.
4. Reed as the awkward geek was one of the biggest problems with the 2005 film. That tired cliche that super-intelligent people are also necessarily geeks needs to be put to rest.