Can anyone confirm the accuracy of the translation below in italics? From reading the translation in other site I get a different meaning.
Original - 土地を離れると信仰を失うが、その地限定では広域の神様よりも(仮に最高神クラスだとしてもそれ以上の)力を持つ事は少なくない。
Translation taken from SoPm, touhouwiki.net - When they are separated from their land, they lose their faith, but within their area, it's not uncommon for them to have more power than wide-ranging (and perhaps even the highest level of) gods.
It's accurate. I assume this part is what you want broken down:
最高神クラス = "highest-class gods"
仮に(...)としても = "even if (...)", "even granting that (...)", "even supposing (...)", etc
それ以上 = "greater than that"
It's saying that gods native to an area can possess so much faith that within that area they can have more power than "popular" gods, even ones that are usually considered to be the most "powerful". It's closely tied to the notion of a god's faith = influence = power.
This explanation mostly refers to gods that have become revered in single or isolated areas, where it's as if the whole population worships the particular god; even if another more widely-known god becomes introduced to the area through e.g. neighbouring provinces, the devotion to the original god in many cases will remain the lead role. That being said, this concept is where the relationship of Suwako and Kanako essentially comes from (Kanako's influence "invading" Suwako's territory) and why it's so significant that Suwako "lost". Maybe that puts it into context a bit.