For the latter question, Lots of people packrat +48 in con swaps to get thick skin and then ditch them.
Not stat points, talent
points. For that matter, now that I think of it, I'm not sure a character gets enough category
points to unlock enough talent trees based on different stats (and then enough talent points to push the T4 talents in them) to end up needing five stats at 54 — and a lot of trees top off at a stat requirement of 44, which I think a level-50 character gets enough stat points to manage for five stats anyway.
[All of which, to clarify, was in service of the original question:
Would it be sufficient to have the planner auto-assign stat points to satisfy the requirements of the talent you just clicked on?
We Apologize for the Confusion.™]
Unstoppable needs 54 strength.
Cripple needs 44 cunning.
Strider needs 44 dexterity.
Thick Skin needs 59! constitution.
That demands deep investment in two class trees and one generic tree.
That adds up to 161 stat points out of 172 but there's one talent point left. Either unlock Celestial/Light from an escort and invest in Providence or go antimagic and invest in Mana Clash and you'll go over.
So, yes, it is possible to get talents that require more stat points than you can possibly have even without going adventurer. Mostly because of Thick Skin.