I don't know if it's my personal feeling but so far, the only useful and with duration sa are those the defenders have.
Defensive wall and Header. I use at least two def. with those abilities. All those past seasons most of my defenders had one or the other sa and I never had a failure in my defenders.
The other one is one-to-one of the GK. I 'm not sure if it's working. The other option for a GK is penalty specialist which is useless.
Maybe can give my GK a handicap against upper lv STs in the Cup.
I intend to keep those players for the next 4 seasons, so it's not big deal to spend some sp for those abilities -
Any way, if I give those sp earlier (instead of adding to skills) they get more slow, so I 'll need more greens.