I don't see any of HotS' changes as being "simple for babies" - I see it more as trimming the fat.The problem with HOTS is that is was basically baby's first MOBA. It was supposed to be a much simpler MOBA for people to get into who didn't want the complexity of DOTA and League.
The problem with that was that it was too simple to appeal to hardcore MOBA players, but not different enough from League and DOTA for people who had already tried those games and didn't like them.
I tried playing HOTS, and while I did like it better than League of Legends or DOTA because it was easier to get into for a new player, I just don't like MOBAs enough to actually keep playing it, and I think a lot of people were the same way. If you do like MOBAs you're already playing League or DOTA, and if you don't like MOBAs there's nothing in HOTS to change your mind.
I tried League, but I was frustrated by the massive item shop, the out-of-game talent system, the long game times, and the lack of teamwork.
HotS remedied all of this, because (at least for me) these things caused more frustrations, than they did improve the experience. HotS was perfect for me, and I know that im not the only person who felt this way.
But I guess you're not wrong. If you don't like MOBAs, HotS isn't going to change anything for you (which I suppose is why Blizzard insisted that HotS wasn't a MOBA, but a "hero brawler"). And if you have already invested significant amounts of time/money into a different MOBA, why bother switching?
I still wholeheartedly believe that HotS had the most potential out of any MOBA out there - but I guess it did come out a few years too late.