[…] but the game is currently easy enough to go through in virtually any configuration.
It would be weird if game required a specific set perks in order to beat it, because otherwise it’d suggest that some perks/builds are not viable and thus are not balanced enough to justify their presence in game (as they won’t be used).
I think most people do not skip tier three perks because they look cool. “Have a taste of my FINAL weapon!” “This is not even my FINAL form!” that sort of stuff.
I feel people are kind of forced to commit a lion’s share of their perks into a specific tree, because of a heavy investment it requires.