Where is Pixie good at?
I think pixie is viable in Arena for not endgame players because her proc does stop procs like SZ, Immo, Vlad, ...
The correct talent should not be 5/5 Revitalize because if she has 5/5 Revitalize what should she remove. She should have at most 3/5 or 4/5 Revitalize then she gives the enemy heroes the chance to proc. You should calculate as well that she will attack in 90% of the cases at first because of her range of 4. Unfortunally as far as I know she does not priotize your heroes that have debuffs because if she would she would be good in Lost Realm. Also if she would target more than 3 heroes she would be good as well in Dungeons and Raids because her heal range is unlimited. She is usefull in Team Dungeons because of her 5/5 scatter which prevent the boss from procing, but that is unlikely BUT it happens.
To conclude for now Pixie is a viable hero if you are not in the complete endgame and have all heroes she can be a good addition for Here be Monsters just because she is a healer but keep in mind that her Skill has a low Damage and healing percentage.
After some more Testing with her there is to mention that she does damage and she heals but only half as much as my Druid. And the damage is half of my Aries. Pure statwise she Has almost the same as aries.
Conclusion is still the same