Well, think about the consequences of multiple reactions to reacting to enemy fire. Every time you'd shoot a bug player, he'd charge 6" closer. Maybe you think you can kill the warrior bugs fast enough, but imagine if that Thorny tanker gets to react each time you shoot it. That'd be pretty scary!
Also, did it really make sense before? A squad of Exosuits could fend off dozens of Warrior bugs charging them right now, and if they can't then they can jump 15" away through reactions. The change makes CC a lot more viable. However, there are some other changes to reactions that people have yet to mention, so maybe not everyone remembers all the little rules from SST:Evo... (and I'm certainly not going to mention them if they weren't stated there!)
The reaction system now makes a lot more sense and works pretty well. Just needs a bit of point rebalancing.