In my experience with titans, their throwing hammer has never been a ohk - unless very deliberately built around melee. It's a little silly that it can be immediately readied for another throw, but beyond that I don't find it to be broken. Warlock grenades, while they can certainly be irritating, aren't gamebreaking. Again it's a matter of someone specializing in one method of combat; exotic armor for void charges, and only playing a specific subclass of the void tree. I make sure to play all classes, but my favorite by FAR is the hunter. Having mobility as the class ability means we move faster, our dodge ability (which I cannot emphasize enough, should be part of your rules of engagement) means either a free melee charge or instant reload - or both, with the right exotic. When I die to a warlock with the supernova, sure it's annoying, but that tells me right away - that's how he's geared up to play, and it requires a simple change in tactics to counter that. Be more cautious, don't engage in CQC, switch over to tripmines, ready a fusion, or sure - grab a shotgun. It's not that this is a 'meta' issue, not everyone plays that way. I see far more people who play based on skill with their chosen weapon set, rather than gambling on a cheap kill with a class ability. Again, I know it's annoying, but it doesn't take much to counter this. Once you figure out how to negate that OHK, within your own play style, these people become easy picking. Good luck, and good hunting.