In response to post #20298009. #20298459, #20300739, #20305349, #20309329 are all replies on the same post.
"If the perk you want has two arrows pointing to it then you need both of those pre-perks to obtain the perk you want. Nothing is broken and it is very clear. I think it even says this in the Requiem manual. Also games such Diablo 2 used the same skill tree mechanism. "
Well, the enchanting-tree doesn't seem to be included in the manual, and I can't remember ever seeing any arrows inside the game. As for Diablo, since I've never played any of these games I've no idea if they've got any kind of skill-tree or not.
BTW, the smithing-tree is especially interesting, since even all perks on the left side is AFAIK connected, it's still possible to jump-over one of the perks to take the dragon-smithing-perk. Also if you take the dragon-smithing perk, if you followed the right side you can only make heavy draconic armour while if you took the left side you can only make "evasion" draconic armour.
Since smithing-tree works this way, the expected behaviour would be any other perk-trees works the same way.