The "General Note" in Civil 3D is one of my favorite things about the program. You give it a size and style and it adjusts to fit any scale you could throw at it. Regular annotative text does not do this. My suggestion: It should.
The whole point of annotative text is to make it scale to fit, but when the scale changes you have to go back in and add or delete scales, or do a number of other things to reset it. Annotative should be given a paper height and that's it.
First off I'll mention that there is a forum for posting C3D wishes so it would be best to post there.
2nd, your wish is more an Autocad related issue rather than C3D since it pertains to the funtionality of generic annotation scale in Autocad.
3rd, you may be overlooking important functions of Annotation scale in Autocad that we do not have in C3D. Often we encounter situations where we want annotation to show at certain scales and not show in others. Consider the case where you have street names on a map. When zoomed out to a large scale you do not want ALL the street labels to show as it would be overly congested. With Autocad's annotation scale you can specify the scales the at which annotations will appear and disregard all others. This eliminates the need to create duplicate annotations to accomplish the task. Also, C3D labels can not be displayed in varying locations at different scales whereas Autocad annotation can. This again is a disadvantage for C3D labels. For these reasons I think many C3D users would prefer to have C3D annotation have the same capabilities as Autocad annotation rather than the other way around.
BTW, you can set Autocad to automatically add scales to your annotation when you change the zoom scale, but that can cause degraded performance so it is not recommended.