I think the first problem of your post is the moment you realized you think (!) that pikes are OP. It was against a clan, and they used masses of pikes. Clan members tend to play together, they are in teamspeak, and unlike in cRPG in strategus they fight to win, not to have fun/mess around.
cRPG has the weird behaviour, that if a class is dominating in a team, the team will win the fight more likely. I don't know where this comes from, and I have no theory how this could work, but as soon as a team has superiority concerning cavalry, archers or heavy infantry, it will win. This is what I observed in cRPG, at least. I don't know how much this applies to a strategus battle, but I wanted to have it mentioned.
Then, if we want to discuss this further, we need to agree on one important thing: noone is allowed to ever mention how "it used to be in history", because this is completely irrelevant if you want to achieve some balance. Warfare in history never tried to be balanced, so it is a very poor base for creating a fair game. It was a rock-paper-scissors-shotgun system, where everyone tried to be the shotgun. For obvious reasons.
That said, I beg you to look at the whole matter from the point of view of a pikeman. Imagine you choose to be one, to play cRPG. Pretty much everyone on the enemy team will prioritize you as a target, either because you are an easy one (ranged, infantry) or a dangerous one (cavalry, infantry). If a cavalryman catches you and a few more of your teammates turning your back to him, you can be sure he will attack you first, if he's smart. If an enemy infantryman is fighting against you and your infantry teammate, he will try to kill you first before trying to kill your mate.
If you get seperated somehow (which happens more easily and frequently than you might think - just follow a good player, and when he dies and you turn around you see the rest of your team that used to be behind you is gone somewhere else), and you encounter an enemy who is not cavalry, you will die. If the cavalry is smart and dismounts before engaging you, you will die as well.
The only thing you can do is to stand in the second line and stab or at least annoy enemies. That's all. Pikeman gameplay is rather plain, and, as most important insight:
No other class is more dependant on other people than pikemen.
Sure, they are great as supporter, but they are supposed to, because there is nothing else left for them. I don't know how it's about you, but most people do NOT prefer to be dependant on other people that much, and if I take a look at the average cRPG player that's damn smart.
A pikeman needs 3 slots for his weapon, no other class besides long maul crushthrough infantry needs 3 slots for one piece of equipment! The only viable backup weapon left is a) a quarterstaff or b) buckler + 1hd weapon (which both need skill/WPF points to be effective).
The most frequent (and dumbest, imho) argument against "nerf ranged spam"-cries was "get a shield", but you are the ONLY class for which this argument doesn't apply, because if you switch to your shield you drop your pike. Because it's not only 3 slot, it's also unsheathable. So you can't switch to a shield while approaching the enemy, like 2hd or halberd infantry.
Then you need to be aware of the fact that a pike is unbalanced. So if you do a mistake you are dead most likely. Or you teamhit a comrade although you hammer on RMB like mad.
And finally I would beg you to equip a pike and try to fight on a steep hill or a rooftop against an enemy. You will be literally unable to attack, as soon as you release your blow your character will do "HNGH", the attack animation will stop before it even started, and you won't be able to block for a second. It's tremendous fun.
We agree on one point though: jump-lolstabs are crap. But not because it's OP or something like that, I just hate how retarded it looks, so I don't use it (and to be honest, I didn't notice any difference in staying on ground or jumping. If anything, I think your damage is higher while staying on ground). I would like to deactivate any attacking while jumping, I hate the looks. People can attack cavalry from the ground almost as effectively.
What I would like to have though is a second attack direction for spear like weapons, both one and two handed. It would make pikemen and especially the poor hoplites more viable. Of course this would change the look of melee completely, with having about 50% spear weapons, and always having 2 lines of combat, but I think game depth would increase, simultanously with the importancy of shieldmen. 2 hd wouldn't be the main infantry class any more. More shieldmen would decrease the general effectivity of ranged fighters, another big problem in cRPG, and the increased amount of spears would make life harder for cav, which is still able to amass a lot of easy, skill-less kills. In short: it would buff infantry again.