Seems very strong since you don't have to get her into combat as long as you have other lifegain synergies too, and Bant seems a good home for lifegain tribal (if you're avoiding the more obvious Orzhov).
Not sure if Bant midrange will have a place in standard, but she could work there. As long as she can survive an attack, you can get some nice value.
What happened to her magic immunity? That's like her defining trait. Why is she a lifegain matters legend now, I don't get it. It looks like her original card got scrapped and they had to shove her into another slot.
The problem with defining this format by what is "fun" is that everyone seems to define fun as what they don't lose to. If you keep losing to easily answered cards, that means you should improve your deck. If you don't want to improve your deck, then you should come to peace with the idea that you are going to lose because you chose to not interact with better strategies.
Shanna picks up blue to draw cards and shift to a lifegain-focused strategy, joining a shard cycle at mythic.
Source: Cracked
Not sure if Bant midrange will have a place in standard, but she could work there. As long as she can survive an attack, you can get some nice value.
Problem solved!