I have no idea why pikes have increased in value. Maybe they're more scarce? Maybe there are some new anticipated universal cards that allow Pikes to be viable?
I'm not sure at all.
I would look into Malangdo enchants, that's a good start.
Str is not as useful as it was, but it's STILL damn useful, however this depends on the base attack value of the weapon, though at very high levels, high Strength pays off for non-weapon/equipment/mastery attack, as the level + Strength bonuses really stack up for some decent up-front damage. Shame it isn't affected by cards though.
Anyhow, it's really Weapon base attack, especially for a level 3 or 4 weapon, especially at high upgrades (+11/12...and if you're uber lucky, since we should have gotten in the "easier to hit +20" system awhile back, but we haven't yet...+13, 14, or the exceedingly rare +15).
Malangdo enchants: http://irowiki.org/wiki/Malangdo_Enchants
There's a list of 1 and 2h spears. You'd want to get Fighting Spirit 4~7 on both attempts...I'd recommend 5 for either as the minimum. Meaning you'd need A Class coins, which require Silvervine Fruit. Realize this is luck based, but apparently, as I haven't used it in awhile, it's easier to get higher and better enchants.
Two solid spear picks for each size:
1H Spears: Hunting Spear , Gungnir 
Sure, the Gungnir is substantially weaker, but the added slot, that it remains level 4, and the fact you'll hit almost everything helps a lot. Just recall your need for elemental change-ups for areas that Wind attribute becomes a bane. Hunting Spear for obvious reasons. Strongest...Brute being the second most prominent monster class after Demi-Human, and it's neutral. Plus that extra skill trigger can come in handy, both for damage, and if the status effects trigger.
Additional solid options would be the Brocca, and even the Battle Hook and Long Horn are worthy options. Brocca of course has no added slot, and low base, but it's level 4, and while Defense isn't quite the issue in Renewal, that it was in Pre-Renewal...it's still damn useful in spots, especially later on. Bleeding from the Battle Hook can be most useful!
2H Spears: Gae Bolg , or Zephyrus 
Clearly you can use Sage buffs or scrolls, or priest to change the element of the Zephyrus, but both would be optimal given level 4, decent base attack, and slots. Zephyrus is better overall. Another solid option is the Crescent Scythe . It might be 1 slot, but you've the advantage of critical hits for normal attacks, and the +10 from the Zephyrus is pretty solid, and +20 off the Gae Bolg. Still, overall output, at higher Strength, due to card slots, gives the Gae Bolg and advantage, especially if you're going in to fight Dragons.
Another useful option is the Ahlspiess. I forget if that extra pierce can trigger off Brandish, as I haven't used that spear in awhile, but if it does, could help. Too bad they never updated the base attack value, but the defense ignoring element helps a lot. Just note that the Brocca is better here, given the base attack difference isn't that significant, and again, I'm not sure if Pierce will auto-trigger with Brandish, or if it requires a single-target attack (I know it triggers with BB).
Brandish, being Melee damage...is better served by either a Bryn for armour, or something with one of the new armour cards. I'd have to sort through them at Divine Pride, and I'm unsure which have been implemented as of yet. Maybe Hayroh will pay you a visit...which reminds me, for all RK users, and I have to agree with his build philosophy:http://forums.warpportal.com/index.php?/topic/154605-hayroh-fatalis-rune-knight-re-17560-water-dragon-breath-update-buildsguide-iro/
So one easier way to skirt around this problem, is by taking advantage of Mora enchants. At least for the body armour. Takes awhile though.http://irowiki.org/wiki/Mora_Enchants
Now the Peuz Plate gives an automatic +20 Atk and +17 Flee. Useful, but you cannot boost attack further, though you can, if the plate hits +9 before you Enchant, get a potential +3, +3, and +4 Strength, for a total of +10 Strength. Quite nice.
The Ur's Plate, however, gives an automatic +1% HP/upgrade, and -5% Neutral and Demi-Human. If you get it to +9 prior to enchanting, there's a chance for getting Fighting Spirit boosts, the maximum will net +12, +15, +21 Attack, for +48 Attack, and +4, 5, and 5 Hit, for +14 Hit. +48 Equipment attack is more often better than +10 Strength...depends on the weapon though, but for an RK, spears haven't seen any serious upgrades in a long long long time. Even the current upgrades on kRO are lackluster compared to a Knight's contemporary physical/melee attackers, or range attackers comparing skills to skills.
Doesn't touch a Bryn though, and there are some new equipment options I'm unsure of.
I also suggest, for Robe, checking into the Heroic Backpack and the Fallen Angel Wing. Fallen Angel Wing is an enchant based item.http://irowiki.org/wiki/Fallen_Angel_Wing_Enchants
Another solid option, though less popular these days, is the Nidhoggr's Shadow Garb, but you should be somewhat familiar with it, as I believe it was released pre-renewal.
Um...oh right, Temporal Boots. There are a few options there that can be useful.http://irowiki.org/wiki/Temporal_Boots_Enchants#Temporal_Boots_.26_Enchants
The Strength boots can be very useful. As can Dex.http://db.irowiki.org/db/item-info/22006/http://db.irowiki.org/db/item-info/22008/
Note that this requires a Rune Knight, and early on, if you're having trouble getting the funds or have the time or the friends to make Mora easy, and aim for those uber boosts, Peuz is a little easier for Damage output, and is better up-front. Overall, Ur is the best set, and the Ur's armour is the better armour. +12...quite nice. Sadly both lack for a slot.
There are a lot of other things to consider. Peuz's accessory is overall the better accessory, in general terms. +20 atk goes a long way, as does +20 SP.
Oh right, one last enchantment system to utilize, and it's quite helpful and fun...improved older gear:http://irowiki.org/wiki/Eden_Group_Crystal_Synthesis