Microsoft are far, far, far from being close to the leader in the market even with ABK on their books, so your FUD makes no sense. Pretty much no one in the entire industry is against the acquisition apart from their main competitor, Sony, who are the market leader and abuse that position every day of the year to pull content away from Microsoft.
ABK will operate like they do currently, just like Bethesda do, only now they have Microsoft money and backing.
The only people that this deal is bad for are people who only play on PlayStation consoles. Everyone else benefits.