Let’s leave the polemics aside and instead quote what an actual individual who holds a tulku title once said about the topic:
“And now, I personally think that to hold that culture, institutionalized Tulku. That culture is dying; it’s not going to work anymore. And even if it… And if it doesn’t work, I think it’s almost for the better because this tulku, it’s going to… If the Tibetans are not careful, this Tulku system is going to ruin Buddhism. At the end of the day Buddhism is more important [than] Tulku system, who cares about Tulku… [and] what happens to them.[6]”
– Dzongsar Jamyang Khyentse Rinpoche, who is considered to be the third “iteration” or incarnation of Jamyang Khyentse Wangpo
Now, back to the topic, acknowledging that the pre-anagami states found in EBTs may allow for multiple lifetimes prior to the disappearance from the (lower) human realms as the path unfolds, I created a separate topic to discuss what EBTs have to say about how could someone at that stage be identified.
I think that may be the closest thing to a well intended tulku - mind nevertheless that EBTs suggest there is a seven lifetimes/reincarnations limit to the pre-anagami attainments. That could be an issue for most the individuals currently assumed as tulkus: with the institution’s age at 800-900 years, most of them are at the 10+ reincarnation! 
Last but not least, and for the record, note that my first contact with Buddhism was through khenpos and lamas from Karma Kagyu. And it was the polemics of who is the legitimate Karmapa amidst the Karmapa controversy that opened my eyes to how troublesome is the concept and dubious the ultimate motives of the tulku institution as a whole. Karmapa tchyen no! 