I think you can probably look at Moshiri's tenure here and split it into two broad categories - his ambition and financing on the one side and the decisions he has made on the other.
Nobody can deny he has put his hand in his pocket and tried to propel us forward. You look at the progress on the stadium and know that this time it's the real deal rather than the Kirkby/Kings Dock/Walton Hall Park debacles we've seen in the past. As far as what he has done with his money and his ambition, I can't criticise. It's been a big leap forward.
As far as the decisions he has made, this is where the problems have arisen. His choices of manager (because Koeman, Allardyce and Silva were most definitely his decisions). The decision to bring in Steve Walsh. Etc
We can only hope that the appointments of Ancelotti and Brands (two proven figures in their respective fields to be fair) are proven to be good ones
Most people seem to equate our performance on the pitch with how good an owner is (or at least subconsciously do), I think it's far more complicated than that. Moshiri needs to surround himself with people who are more experienced at making football decisions - Brands' appointment is a good step in that direction and, arguably, even Kenwright's continued presence helps in this regard (*dons tin hat*).
He's put his money where his mouth is, the rest of it is down to the people he employs