If Battlegrounds ends up being another way for players to enjoy Hearthstone, then that itself is a fine addition. If they intend on pushing this and making this an 'E-sports' thing, then it will not work without a changing metagame of minions and heroes.
Which they are literally doing. https://www.reddit.com/r/customhearthstone/comments/dvi0iw/design_the_next_cool_hero_for_battlegrounds/
You've had a lot of criticisms that are pretty easily answerable with a tiny bit of digging.
Edit - I went to the thread. Some of my questions were answered, so fair enough. But not everything. I am still waiting for a release schedule and how often this game will get support.
Also, after some 'digging', I found this forum post on the official website.
Yeah, don't point people to reddit when the official announcement is not even on the official pages of the actual game site. It is not my duty to go looking on third party websites for information that is 'official'. As someone said in the thread above...you CAN post in reddit and other places, even if Reddit is more popular.