This is about risk and cost.
This is not something that will help contractors. The main disadvantage of the current rules is that the risk sits with the client, not the contractor as it used to. This means that previously companies could pay someone a rate and offer a contract that suggested outside IR35 but then if HMRC disagreed it was the contractor on the hook. Now the client is on the hook if they haven't done the assessment correctly. Their only way to mitigate this risk is to move away from PSCs and go umbrella but that has proven to be expensive - I don't pay more tax in an umbrella, the client does because my rate went up to reflect their choice so I take home the same amount each month.
Gov.uk has already started to erode this a bit by discretely changing the rules so the risk can be shoved back onto the contractor if it is found that they misled the client on the IR35 assessment. Any review will be a further erosion of the responsibility of the client as those risks are shifted back onto the contractor. As for how HMRC interprets things, they have proven to be a law unto themselves when it comes to how the rules are interpreted. I can imagine they would be happiest if the contractor paid taxes like an employee and had all the risk while the clients would like to pay rates that are more in line with permies.