I'll quickly go over why Warden is utterly broken and why Warlord might need a nerf.
Warden = she attacks too fast, that's all there is to it. Her light + heavy attack combo is broken. She has no counter play to her and she can hit you out of your: Heavy Attacks, Light attacks, Unblockables, and Guard Breaks. That's ****ing ridiculous guys, she can even cancel your counter strikes if she is good enough. The only thing that is decent at stopping her is unstoppable attacks (like raider), yet the ***** can just dodge out of those too. I feel like in your quest to make the Vanguards different you forgot to keep balance in mind, because it's pretty bad looking that you let this pass in a game based around timing.
Warlord = Less OP then warden. His defense is too good to have that much damage with that fast of light attacks. I can beat a Warlord if I'm way better then him but if he's on par skill wise I will lose. At least you can guard block him, unlike Warden. The Warlord one is slightly new so it's probably just me not understand them well (even though I've played against them quite a bit). So if you have a counter argument on why Warlord is fine I'd love to discuss it.
How to balance them.
Warden = Remove her fast heavy attack completely, or make her have less health then Orochi. I would suggest a complete rework because half her combo's are braindead and borderline useless. Warden is a one-trick pony that works because she has no counter play.
Warlord = Just a small stamina nerf, make him run out faster for using his block. His light attacks are broken only because he can spam them and block constantly.
I played a small amount of Alpha and played full time on Closed (and now Open) Beta. People who say Orochi or Raider is Op haven't played enough IMO. Orochi is annoying but when you learn what heavy attacks they can't dodge out of they become pretty easy. Also positioning is vital on defeating an Orochi, make sure you move the fight to a confined space if possible. Raider's heavy attacks are very slow and easy to counter and I honestly find them the easiest class to deal with next to Peacekeeper.
If you think I'm missing some big key counter to Warden, then please tell me.
Fast attacks?
The pk has fast attacks, the orochi has fast attacks, the berserker has fast attacks and the nobushi has fast attacks. Pardon. The nobushi has freaking fast,attacks.
The kensai has way faster attacks, that the warden as well.
Yes - the perma stagger sucks but the warden is hardly the fastest hero. He is in every department average.
The assassins are hard counters to the Warden. Not only can they use the reflect to open them up, but the Orochi can counter-attack after said reflect AND he can do the back-dash attack rush, that you can even cancel into a guard break or a heavy, and then even cancel that if you wanna mess with their heads even more for a light attack and have them guessing at what you're doing non-stop
I wouldn't say that the Warden is OP, especially compared to some characters. I would say that he can exploit the weak double side attack and guard break however. I'm not that good with a Warden, and I have destroyed people who were probably better than me (when I play as warden) by simply guard breaking, right double light attack, guard break, left double light attack, right double light attack, guard break etc. But I think that could be fixed by making the second hit in the double combo take a little more stamina. It won't stop it from happening, but it would make exhaustion happen quicker to give the opponent a fighting chance. As it is right now its kinda a Paper, Scissors, Rock game once someone gets locked in it. I do know that he definitely isn't an quick as Peacekeeper, although I'm not sure about an Orochi, but the Orochi is probably quicker.
I really have no feelings about the Warlord, as I haven't played as him or against him enough to form an opinion, but seeing how people either flock toward the OP Characters, or those who have the best chance at fighting the OP Characters, coupled with the rarity with which i see warlords, i would have to say probably not. I did run into one Warlord who whooping me pretty consistently, but it felt like he was just better, not that his Character was OP.