There is already a two-handed pole arm that does piercing damage (and topple) in the table - the Lance (which is literally right below Halberd in the weapons table). The problem is that they included an illustration of an overly short tournament-style lance, rather than a typical military lance, which was just a big spear that could be couched. It's also worth noting that the pike in the PHB illustration is only a little longer than the halberd or glave, which makes the 18lb weight make even less sense.I'm of the opinion that the pike being on the main equipment list is just a relic of past editions. It really shouldn't be? It's a weapon that should be fielded by armies, like a trebuchet, not by adventurers in a dungeon. It's not really even a complaint about historical accuracy even, just logistics and the fact that it's redundant with the halberd.
There's even an actual historical weapon called a spontoon or 'half-pike' that would make a lot more sense as a dungeoneering weapon.
But if there were a typical 20' pike available, I wouldn't entirely mind. One of the things that seems missing to me in DND is the sense of using the right weapon for the job. If one is going up against a huge beast, you don't want to run in with a sword or dagger (though the image of a Rogue jumping on a dragon's neck and stabbing away at the back of the head is pretty epic), you want a giant pointy stick with serious reach and penetration. Going after a dragon or T-rex, I would want a couple of people with pikes to hold them at bay while the archers and spellcaster wail on them from range. Or trap it with nets and skewer it with some reach. But having that level of tactical flexibility runs into option bloat.
Personally, I would love to bring back the old pole-arm table for flavor, but keep the mechanics simplified, with dozens of options for Partisans, Billhooks, and Batwing Corsecas as Heavy, Reach, D10 weapons with either Slashing & Cleave or Piercing & Topple.







