I really struggled with this on my former stove. Was suggested my chimney was not correct, wood not correct, something other than the stove doesn't breathe well. Get a slow fire started, it struggles, crack the door and the load bursts into flames. Close the door I sat and watched the fire slowly whimper out, and that was with fire starters, too. Didn't matter what I used. So, I started putting a small hair dryer under the stove and fed air into the box. Raging fires. Turn it off, watch the load die out and so, crack the door and wait ridiculously long periods of time for the fire to build in strength, smoking away. Drove me crazy. My chimney is 8". Bought a 6"liner which barely squeezed into it, so the actual diameter is less than 8". No improvement to write home about. I gave up.
Changed stoves, same set up, zero problems starting the stove even with the temps in the low 50s outside. Why? The new stove has no long channels for air to travel through. Direct in at the door, direct in on the secondaries.
I'm certainly not saying all Phase 2 noncat stoves suffer this problem, but many do. It's common sense in the overall design.