Well going by your video and some things you've said you're either on an outdated GoG version or on a pirated version. The AP eating glitch was fixed already.
Secondly you delayed your first turns even though there were obviously several ranged enemies nearby. You have to expect to take a lot of damage if you do that and possibly have characters frozen/stunned.
Thirdly, if both characters are lone wolf you should have gotten Glass cannon so you can at least take actions equal to 4 people. If you choose to make the game harder on yourself without understanding how it functions you shouldn't come and cry about it. you should have done something such as attempting to free the nearby archers/mages or setup a smokescreen so they couldn't see you, or knock them down, or make it rain and use lightning to stun them. You had a ton of options.
You also shouldn't complain about possibly needing a certain character type for hard mode when it's called hard mode. And you should give your melee guy a 2H weapon if you want better damage out of him. Like double the damage. And warriors start out not as strong since they simply don't have the AP to do much early, but later MaA skills are completely and totally broken to the point where you can kill a boss in one turn with them. You're nowhere near far enough in the game yet to make any proper judgements on character builds/strength
Im probably on an outdated version which i should fix.
Secondly yeah i know i was just showing what happens but even if you don't delay your turns the same thing happens (trust me i've tried before that, unless you can get to a fight without facing all enemies at the same time it will always happen)
Thirdly i dont have trait for glass cannon just yet , i dont have lightning and even if i did lighting + rain id stun just one (probably) and there are still so many free , i really didnt have a ton of options
fourth yeah so bad classes go home? That wont ever fly in a non-single player game but i see/understand your point here anyway, as for not being far enough to judge - why not ? the first half of the game is also a part of the game so how come it suddenly doesnt count..
perhaps i should just go with what i see as strongest as im playing on hard mode and not really care about balance because maybe its balanced over other difficulties but whatever..