There are many threads regarding different polearm builds, and some good posts about pikes. You might want to browse the forum a bit, to get more information. Anyways, here is my input:
I have used polearms for about 2 months now, a +2 Poleaxe and a pike. 24/15 Str/Agi. Have around 145 WPP in Polearms.
If you want to use a pikes as your primary, i would definitely go after more Power Strike / Strength. As a dedicated pikemen I would go 27/15 with light armor...
If you mange to find a thread dedicated to pikes, you will see, that many players are suggesting high agility/athletics... Well, i can only use my personal experience, and i do not see any use for high athletics.
In "theory", you need athletics to run away from your enemies, in order to keep them on a comfortable distance. In my personal experience - if you are in a situation where you have to duel, you will need to drop the pike, and use your backup weapon. A peasant will not try to "hunt you down" anyways, and a good player will block your every strike.
If you are in a situation where the pike is most useful: supporting attack/defence while being covered by friendly troops, you will not need athletics at all. As an example - just yesterday, I had 15-20 kills on EU Siege for few hours in a row, using a pike, a voulge, and a set of peasant cloth armor
It might not always go so smooth, but never due to a lack of speed. Not for me at least
With 8 PS, i only need to poke 1-3 times before enemy drops dead. Archers die instantly. Horses colapse. Shields crumble.
I would still invest 130+ WPPs in polearms, as you have to use a backup weapon, something fast, like Bec or Hafted Blade. If you only have a pike, many will try to deliberately hunt you, after you kill them few times
Just up your STR/AGI to 15/15, and see if you
really need this extra athletics, or you want to get more damage. That will be the easy way to test it for yourself.
Good luck!