Okay so basically this build destroys me everytime, and even if I do manage to hold it the zerg has their third up and can easily macro. Granted I lose to this when i go for the reaper hellion opener, but still could use some pointers if anyone has found a solution to this.
I currently do reaper hellion but I'm switching to reaper hellion cloak banshee, maybe with the viking first like Polt does it. I end up with the same or better medivac push and feel much safer against all-ins.
If you're gonna go reaper hellion you pretty much have to scout like a pro in order to be prepared for this. If you scout any indications of a roach build just having 1-2 safety marauders and 3 bunkers should hold it. Also you can have mines instead of hellions but neither of them are particularly good vs roaches.
You can bring reaper/hellion back to help you defend but they're pretty shit vs roaches without micro so I sometimes go for a runby to do equivalent economic damage or more than what they will do with the roach attacks.
Here's an example replay of mine where I did a runby after scouting a roach allin very late. Take it with a grain of salt since judging from his portrait he's won 1000 games as Protoss. But the point is I try to keep the reaper/hellion alive as long as possible and kill more workers than he does while I build up an army that can kill the roaches.
Keep in mind the idea is to scout like Taeja and never have to react to a roach allin so late.