Putting powerful effects in the finisher means you lose a lot of the value of a tree unless you get all the policies.
So what that effectively means is:
Whatever the finisher bonus is, is just that, a bonus.
You like 4 of the policies but think the last one is 'meh' but by taking it you also get the finisher.
Let's imagine a policy tree with no pre-reqs. 4 of the picks are 'good' and 1 'not-so-much'. The finisher is 'so-so'.
You pick the first 4 'good' ones and think why choose the last, it isn't worth it. However the last pick is now 1 'not-so-good' + 1 'so-so' which might make 1 'all right' pick.
Now if this tree was rearranged so that the 'not-so-good' pick was a pre-req for a good one. Would you hesitate to pick it? No! You then pick all the rest, because they are 'good' and the end result is the same.
What we choose and in what order, is determined in part, by the pre-reqs.
Not only within that tree but by what we want in other trees. Having a desirable finisher in a tree that has 1 or 2 not-so desirable picks is just another order of decision.
Sometimes I would really like to get all of one policy but circumstances dictate I choose something from another policy to face a new situation. Now that I am not forced to complete policy trees, 'Finishers' stand up on their own merit. If it is really good and I need 1 or 2 weaker picks to get it, it just makes my choice more involved.
Making policy picks or finishers better or worse based on how soon or early we can get them is a trade-off system. Are we willing to invest our picks to get the desired result.
Whether it is "painful" or not is subjective. IMO some of the
in-tree policies are painful to reach. We can't move all the 'good' ones to the front.