Aptitudes in 9.1 were the good part of skill system imo. I mean: you can deep for 1-2 skills in one line, but you also need to put points in aptitude to do that, which means that 1 skill will cost you twice more, 2 skills will cost you 50% more. The more skills you have in line, the cheaper they get. And it was really smart. Now we have tier system instead. It is not strictly worse, just different (for me, at least).
But i can agree that spending point into nothing feels kinda bad. It is ok, when you have 50 skill points, but pretty bad when you have 15. Maybe if the aptitude points would give some kind of bonuses on their own, or enhance the skills associated with them, it would feel better. For example: you need only few skills at tier 2 in Leadership, but level 3 aptitude makes them more powerful, so you have a reason to put a point in aptitude.
Also i want to say: even if we will get phase OPness fixed, Derelict contingent reworked, ability to pick alternative skills in already opened tiers and more adequate DP limits, there will be people who want 9.1 system back. Now we have 55/45 percent distribution. Then it will be 25/75, i guess. May be 20/80. It is still big part of comunity. So, what i want to say: different people want to play game in different ways. Some like the level cap. Some want the ability to pick every skill. One of the 9.5 goals was to make skill system more newbie friendly, but some people want hardcore character building like in PoE. So, maybe it is better to make mods implementing different systems? Is it possible?