Well, I must say that halving will be helpful for those miners who already know about it. There are many mining farms that will sell their ASIC miners for cheaper rates before and after the halving event, and the determined miners will get a chance to purchase those mining equipment for very cheaper rates. After halving event many of the current miners will stop mining due to less profits from mining operations and that's why the mining difficulty level will drop by significant levels.

But, I must say that those miners who sell their mining equipment and halt their mining operations are the naive ones. I'm calling them naive because they aren't aware of crypto market and the bull run that's going to take place after halving event. Those miners could earn a lot more profit during halving event if they don't sell their equipment right away, but I'm quite sure that most of those miners are just calculating their daily earnings from mining operations and they really don't care much about holding of their mined coins.

There won't be much impact on the general ecosystem of the Bitcoin, but surely difficulty levels will reduce to good levels for at least 2 to 3 quarters depending on some factors. Let's suppose that during the halving event some new and powerful mining equipment are announced and once the miners get those equipment in their hands then the mining difficulty may rise after some time when those ASIC mining equipment's become functional for miners.