Off time can be converted into a dream like situation. At the time of activation users can see a fast time highlights to reduce the time.
Incarnation may seem to be scientifically unrealistic but Everyone almost believes in another life. The religion angle needs to be put in. Though in voluntary society no one can choose it but in real life it is like that.
Making aging only criteria to die is also not perfect. Though most of the games never consider aging factor because it is not too adventurous. We can put other life experiences disease, accedental situation etc. By doing so, one can loose some power of Incarnation if he mets such situations like TRA. A death by aging will always incarnate the user in next life but a death by other means will not, though a single incident must not kill the user but makes him vulnerable to next life threatening incident.
I can put other suggestions too if it will be helpful. My ideas may not be ideal but sometimes random thoughts are more striking than a brainstormed one.