vezoz haberacha / hoshana raba

The posuk says ויעל משה מערבות מואב אל הר נבו; Moshe went up from the plains of Moav to mount Nevo & 'ה showed him the entire land of ארץ ישראל, & said to him, this is the land I promised  אברהם, יצחק & יעקב that I would give over to their children. Look at it, but you're not going to enter.
Rashi says that 'ה showed it to him so that he would tell אברהם, יצחק & יעקב that He fulfilled his promise to give the land to their children.
How does Moshe see the promise fulfilled? If he believes 'ה that he's going to bring them in, why does he need to see the land? And if he doesn't, then how does showing it to him help?
We see a similar thing when 'ה gave Moshe the לוחות. He said to him, go down from the mountain; your people are sinning. Moshe takes the לוחות, goes down, sees them sinning, then breaks the לוחות. Didn't he believe 'ה? Why bother taking them down to begin with if he's just going to break them?
The last Posuk in the Torah says אשר עשה משה לעניני כל ישראל; what Moshe did before the eyes of the whole Klal Yisroel
Rashi says what it's referring to is that he made sure to break the לוחות before their eyes. However, isn't that obvious? We just said he saw them sinning & then broke them, so of course it was before their eyes!
The שפתי חכמים says that it should have just said לבני ישראל. Why does it have to say לעניני כל ישראל?
Maybe the reason it says לעיני is to teach us that Moshe had to do it in front of them. He had to go down to them to see firsthand what they were doing wrong.
Similarly, over here, of course Moshe didn't doubt 'ה. However, how could Moshe tell the Avos that 'ה fulfilled his promise without at least seeing the actual land firsthand, the same way he wouldn't admonish the people before he actually saw them doing wrong with his own eyes.    
The פוניבז' משגיח used to say that the same way the עשרת ימי תשובה are days to reflect & turn, and better our ways, and יום כיפור is the seal, so too are the ten days from יום כיפור until הושענא רבה and הושענא רבה is the ultimate seal.
Now if הושענא רבה is the ultimate seal why don't we fast and daven like on יום כיפור ?
Maybe it's like we're saying here that the days from ראש השנה until יום כיפור were the days for us to reflect & repent, but now in the next ten days 'ה comes down, says the פוניבז' משגיח to see if we are really doing what we said we would on יום כיפור, without the fasting and davening. Just seeing how we act in our daily lives. Then once 'ה sees firsthand that since יום כיפור we're busy doing the mitzvos and bettering ourselves, He will put the final seal on a great year for all of us!