Hello, my new fellow pikeman, maybe you know my pikeman alt named Pecores_Kofilin.
I use the 3m Pike on that one and have a 15/24 build like you (with more armor though).
There's nothing "special" about the pike and the long spear damage-wise, but they both are very special weapons, in different ways (the 300 reach one really being a total UFO).
Generally, it's possible to fight normally with the long spear. Tricky, but possible. However, (afaik) defending yourself with a 300 reach pike = suicide. You can't attack. Too high reach turns you into a retard-looking backward jumping guy, and in case you can hit, any decent opponent will block, you will be stunned and can't block the next swing. Now if you try to block everything until some ally helps you, it can be very difficult too, even for a decent blocker, because the block speed is extremely slow. No last second blocks like with any decent melee char. So not having a sidearm makes you terribly gimped.
Personally I'll go 18/21 next gen, as I bounce too often with PS 5 (usually when my angle is not good or the timing is a little wrong but those things happen).
I think 15/24 is a pretty solid build for the long spear too, though. The weapon choice depends on how "pure" you want to be.
Personally I've found high str builds to be better for long and slow polearms. With pure str you can still get to over 100 in polearms and that's more than enough for a pike, I can use them on my 2h with his 0wpf in poles because of his high str
It's true you have more than enough wpf with low WM. But agi and athletics are the essence of the "I'm everywhere at the same time" skill, which is really important for pikemen atm because there aren't many (good) of them.
