So... I can't really answer the question. But I'll venture the opinion of a representative of the worst possible group to respond to this question: a white, straight, right-wing male.
I've had two gay players at the table, one of whom I consider a very long-time friend (rather than "just" a gaming friend; i.e. dinners, parties, shared experiences). Neither is currently playing at my table, but only because they're now living in different cities. I'd welcome either back in a heartbeat.
I've also had two openly bisexual players at the table. One moved away several years ago but I'd welcome him back. The other still plays with us, and is a valued member of the group.
All four started playing D&D years ago. I've never heard any of them express that they felt either the game or the group was anything less than inclusive, despite us being the most politically-incorrect table you could imagine.
My personal feeling is that the new official stance is a great thing... but in practical terms, it changes nothing at our table. If we bring in a new gamer and they're LGBT, it's irrelevant to everyone at the table. It's just... not a thing. It never has been. As for the new player, I think that their sole reaction to the game is going to be based on whether they fit with our (fairly shocking) sense of humor. I've seen straight white males not stick around because we were a little too much for their sensibilities; I've seen a bisexual polynesian female have a great time because she was as demented as the rest of us.
I don't think a new LGBT recruit to our group is going to be swayed by four paragraphs of text in the PH. I don't think they'd be swayed by 40 pages of text in the PH. It's about the people, not the game, for us.
Part of my "I'm not sure that it makes a practical difference" attitude could be because I've found that gaming in New Zealand is a little different from gaming during the 4 years I lived in the States. As a society, Kiwis are pretty darn liberal (and even right-wing Kiwis like myself see "liberal" as a positive descriptor, not a slur). We have gay marriage, and legalized prostitution, and openly gay or transgender or weed-supporting politicians, and we're thinking of changing our flag, and our environmental party holds 12% of the vote (and parliamentary seats; we have proportional government, not two-party), and our ruling right-wing party is a little bit left of the democrats. Gaming, in general, seems to be fairly popular in the members of the NZ LGBT community that I know, and always has been. But, again, it's a slightly different environment here.
Nonetheless, kudos to WotC for the official stance. I like seeing it. I support anything that increases the diversity and inclusiveness of the player base.
Is it sufficient? I have no idea. Everything I've said above is colored by my own boringly predictable gender identity.
What I absolutely do think, however, is that I get nervous when I see people responding with: there's no place for sexuality in D&D. The actor Matt Damon recently made some comments about how gay actors shouldn't come out of the closet, because there's no place for sexuality (straight or LGBT) in acting. Actors should apparently be sexuality-blind, and happy to play roles on any side of the fence. But, regardless of whether he had well-meaning intentions, I feel his comment missed the broad point. It's fine... and expected... for Matt Damon to stand on the red carpet at a movie premiere with his wife, and give her a supportive kiss. It's a different story if Matt Damon shows up on the red carpet and kisses Hugh Jackman.
The same is true in D&D. If there's no place for sexuality in the game, that's still not addressing the fact that everything is so very heteronormative by default. Tika Waylan at the Inn of the Last Home will flirt with the buffest party fighter, the princess in the Bloodstone module series will marry the highest-charisma male PC when she's rescued, AD&D nereids will drown males with their kisses but women are immune... It goes on and on. There's no place for sexuality in D&D, unless it's the same sexuality we've been seeing for centuries. Yeah... no. I'll take some variety, any day.