It's a shame that he probably won't learn from this experience because he will not know what he did wrong. Of course you are certainly not required to tell him. It would be difficult to do so without coming off as preachy anyhow. I think you handled it well.
Reason, as a guy, let me ask you this: if you were in TextGuy's shoes, would you appreciate a kindly-worded heads up, something along the lines of "you seem like a nice guy, so if you want, I can tell you what put me off about you, and maybe it'll help you next time you meet someone."
Of course, the woman in the situation would have to be very, very clear that she's not saying "fix this and I'll date you." If that *could* be made clear, would it be a helpful or a rude thing to tell him why his approach isn't working?
Guys are all different, so it's much safer not to offer input especially after just one date
Personally I would appreciate input on what went wrong, but that wouldn't mean to me that the next girl would not like the same thing. I would never ask for input on what went wrong though. For example I was once told that things aren't going to work out because I opened the door for a girl I was dating
. Apparently that makes me a male chauvinist. I appreciated knowing how she felt and this case she was certainly right, things were not going to work out, but I still open doors for people.
Even for the guy in the OP, he may very well find some girl that finds constant twitter like updates of his day to day activities and his apparent neediness endearing. Doubtful, but possible. However if it's something obvious like "I don't think this is going to work out because you chew with your mouth open and talk at the same time" then I see no reason not to let the guy know.