my mother has had 8 c-sections. I do not believe she was ever told about a thin uterine wall in her case though, so I don't know what to tell you about that. She had all bikini incisions, and she said that the recovery was different with each one. Some of the later ones were better than the earlier ones, probably due to her health, doctor's skill, baby's position, how much she was able to rest, etc. All went well with the first 7. In fact with her seventh pregnancy, the doctor offered her a trial of labour! (Which she had begged for with her second and third babies, but was denied.) She didn't feel safe taking that option after six, (nor would I), so it was another c-sect.

Anyways, with her 8th, she ended up with placenta percreta, where the placenta adheres to the scarred portion of the uterus and grows through it. It pervaded her bladder as well, and caused major haemorrhaging and required her to be hospitalized at 19 weeks. In many cases, the recommendation is that the pregnancy be terminated. However, my parents would not do that, and her condition was never actually diagnosed conclusively until delivery. At 28 weeks, after another couple of major bleeds, my brother was born. They did a total hysterectomy and bladder repair. (BTW - my brother is a happy, healthy 8 year old now.)

Placenta percreta or accreta is a danger with a scarred uterus, and I think you should be aware of the risk, and factor that into your decision making as well. I'm not saying you shouldn't have more children - just make a well-informed decision, and get a good OB!
Try googling caesarian and thin uterus, or placenta accreta, and see what further info you can come up with to discuss with your doctor.

All the best!