It's a good point but not an overwhelming concern. Please understand that I'm not speaking just from looking at a render, I am exceptionally well familiar with both of these sites. The render isn't facing due North, it's facing NE, the same basic direction as Fenway, which I'm sure isn't unintentional. But yes, opposite the direction of the setting sun, but it's not necessary to be completely opposite. My preferred orientation would turn the stadium 60 degrees or so, facing NNW, which is essentially the same as McCoy. Take a look at the satellite image, imagine homeplate drawing a line through dead center up to the Slater Mill. So yes, you will have some similar sun issues as McCoy now. So the first base side fans have to deal with some sun the way they do now, during the month around the solstice. Maybe they've identified that as a big customer complaint and if so fine.
Brohammer you have to shore up the edge of the river no matter what you do with the site, even just put parking on it. By Riverside I'm not talking the same height as the river, though you could probably do something like they did across the street under the 95 Bridge, too.
I also hate hate hate the idea of replica Fenway. Real Fenway is 45 minutes away, this isn't Greenville. I mean, maybe kids would love it that way, I don't know. But it feels pretty gimmick-y.