So fighting ISIC would allow him to just spam his cannon and stop you in your tracks until you die (melee characters have no chance of survival) Boldur would prevent anyone from using any skills which would do nothing to prevent his target from just walking away like he’s just an annoying fly.
The fact is that this game is not World of Warcraft or an equivalent. The characters need both offensive and defensive capabilities while also being balance. Making a character too strong/weak in one area defeats the purpose of the character. Each character needs to be able to be fully capable in their own right. Again, maybe these characters just don’t fit your play style and you could play someone else. It is also possible this game is not for you. Complaining that a character isn’t exactly what you want it to be when the character doesn’t fit that role isn’t going to help the situation.