It's true--Azrael was slated to take over for Batman of all things, so he was going to be accepted and have success without earning it any more than her. (Of course, he also wound up crazy, right? I wouldn't want to see Stephanie got some sort of weird power boost and got promoted only to then go crazy and flame out. That would seem more like a punishment.)
It seems like at least some writers do see her as needing to evolve since Tim is. I don't think that evolution has to mean that she becomes a better vigilante, basically the same but without these issues. Or of course she could keep being Spoiler and just operate on a lower level, though that's what I feel like she should try to avoid.
I don't want to say how she should be written or anything. It's just that often Batman's attitude towards Steph and training doesn't make sense to a lot of people so I just feel compelled to say that it does make sense to me. Which is not to say I think he's treated her well. There's plenty of times where he is using her to act out his weird emotional issues. I just don't consider the not wanting to train her part of that, if that makes sense.