Line of Sight - This is only for activated direct damage attacks. Melees have very few to none of these. Only a few specs of ranged have them. So this isn't a counter to instant direct damage specs. And to the extent it is, it is also a counter to DoTs as well.
Kiting - Balance Shadows, Pyro PTs can be kited. This has nothing to do with DoTs v. Direct damage, it is a function of range.
Push/Knockbacks - This is not a counter to an instant attack. Once the attack lands the damage is done. It's actually a better counter to a DoT spec. Often I will push a DoT spec away and run out of LOS. That gives me time to let the DoTs expire or for me to use a heal/medpack.
All of these are counters to direct damage attacks, though not reactive counters such as a cleanse is to a DoT, but rather counters that needs to be used proactively.
For melee the counter is to prevent proximity, for ranged it is to prevent Line of Sight. Those issues are negated with (most) DoTs being delivered instantly and keeping on damaging regardless of proximity and/or line-of-sight, aswell as outlasting (most) damage-reducing cooldowns
That's not an advantage. What you're saying is that DoTs do their damage so slow that they outlast cooldowns while instant attacks just get eaten. Well, if you are crazy enough to waste your big attacks on someone who is using a 3-5 second cooldown then you deserve to lose. But DoTs have to apply their damage over 6-18 seconds. And for damage that is not superior to what direct damage specs can apply in the same timeframe.
What I'm saying is simply that unlike direct damage, DoT effects will only be partially negated by a damage-reducing cooldown, granting them a relative (though questionable in practicallity) advantage over direct damage, as they would have the entire hit negated/mitigated. This is purely a relative advantage though, and shouldn't be taken as a meaningfull factor, in off itself.
The thing is DoTs aren't any harder to counter than direct damage. In fact they are easier to heal through, can still be shut off by purge abilities and telegraph themselves for healers. People got used to being able to push a button every 4.5 seconds to shut down DoT specs, but it plainly isn't fair or necessary.
Agreed (except for above mentioned exceptions). I would merely argue that simply making DoTs incleansable is merely pushing the "dumbing down" factor to the other end of the spectrum, where there are (nearly) no way to counter the classes using them. Neither having a 4.5 seconds "auto-win" button versus DoT-classes or simply making them uncountable is fun gameplay, imo. Which is why I hope a discussion of the "pro's and con's" of the uncleansable DoTs will inspire the Devs to make a more sustainable and fun solution to this problem, rather than simply keeping "status quo"