i don't think that all beings are ultimately enlightened though i think everyone has the potential to be enlightened.
Unless we are enlightened, i think that our view will tend to be flawed. As such, I prefer to trust beings who have achieved a higher state of attainments to guide my view. I think that I should not be so attached to my own view as it is likely to be wrong. Sure we can use conventional wisdom but is that correct view? Conventional wisdom used to think the world was flat.
Personally, why I choose to view HH the Dalai Lama as a Buddha is that if he is not, it doesn't really harm me. If he is, and I think of him negatively, it will affect me negatively. While I believe that he is a Buddha and I do not agree with his ban on Dorje Shugden is because of the bigger picture hypothesis which I learned from the sharings on this site.
Of course there will be many people who see the Dalai Lama negatively because of the Shugden issue. Conversely there are a lot of people who see him positively. From Dorje Shugden's lineage, Birwapa was condemned as a womaniser even though he was in reality having audiences with Vajrayogini and her entourage. It was people's wrong view though they could justify it very well that he was a man of loose morals from their direct observation.
Likewise, in this modern age, are we at the level that we can judge? Is our conventional wisdom really so wise? Or should we trust enlightened masters such as HH Trijang Rinpoche who tells us to not lose faith in either Dorje Shugden nor the Dalai Lama? Such as HE Gangchen Rinpoche and many other great Lamas who do not criticise the Dalai Lama? Are we so much cleverer than them? Or rather, do we think we are so much cleverer?