To answer your question: Yes...but no.

Typically textile motorcycle jackets are made from heavy denier cordura, usually doubled up on the shoulders and elbows because of the need for extreme abrasion resistance. Add to that shoulder, elbow, and back armor, plus the waterproof layer in the liner and they can be stiff. But I find that motorcycle jackets are generally tailored much better than the average coat. A good jacket is sewn with bend and/or twist in the arm (lets face it, when you're wearing a jacket, how often to you keep your arms arrow straight?) and are very form fitting so there is little to no bunching or buckling. I like motorcycle gloves for the same reason. Sewn with a curve in the fingers and the palms seams are cut and sewn perfectly so there are no pressure points on your hands and don't bunch under your hand on the grip.

Also, the armor comes out so if I didn't need it during the winter I could cut bulk and weight simply enough.

Secretly, I like the armor. Once one of my friends was screwing around in the garage and I took a baseball bat to the spine (not a full swing thank God). Without that back armor it could have won me a trip to the hospital. I know of several people (they live on the wrong side of the tracks keep in mind) who have upgraded the elbow/forearm armor on their jackets for protection from knives. The jackets don't cut easy and hard armor is almost impossible to stab through. Some jackets have a ripstop design like ripstop nylon only with titanium threads instead of heavier nylon.