As has been pointed out in the PTS forums, it's quite possible that a rate limit on charge loss or an increase in number of charges would help offset the increased spikiness since 2.0.
Frankly, I'm all for a rate limit (maybe 1 charge/s) as it will significantly smooth the DTPS profile, even if there are scenarios where we'll take more damage, and the smoother profile will make it easier for BioWare's flawed metrics to make an accurate accounting of our survivability.
The problem is that these aren't new suggestions: they've been suggested from the very beginning and, honestly, it looks like the developers are no more likely to implement them now than they did at release. Hell, it took the developers over a year to remove the Force cost from KW, something that had been mentioned as an unfair mechanism for just as long (no other tank has to spend resources regularly on a pure survivability mechanism).
The mechanism I've always supported has been KW stack *regeneration* through the use of certain attacks or conditions. Imagine if defending/resisting an attack *generated* a KW stack or scoring a critical hit with Project, Slow Time or Force Breach generated new stacks. Either solution would solve the primary problem with KW disappearing too quickly when it's supposed to be a constant benefit according to all balance math we've ever seen, not to mention working better with the current stats (so that Defense actually serves a functional purpose beyond just mitigation, since, as it stands, the mitigation benefits are questionable at best) and ability layout (since there's almost no reason to use PA since it's so inefficient; getting a guaranteed crit with Project to generate 2-4 new KW stacks off of the KW CD could actually make it a *useful* survivability mechanism).
I still think that the design of Sin/Shadow in 2.0 is a little suspect, as the level of competence required of both the tank and their healers is higher than in live, and significantly higher than with either other tanking AC on either faction. If, in fact, Sin/Shadow is still the sturdiest tank by a fair margin, it's almost a fair compromise, but I'd rather see a rebalance that makes an experience with an "average" (read: bad) Sin/Shadow less painful.
I find it amusing because this is exactly how it was when TOR first released: a lot of tank Shadows were utterly terrible and, as such, the class/role as a whole had a terrible reputation; those few of us that knew how to play them and could play them *well* showed people that Shadows were *amazing* tanks when you didn't just facetank things. It seems to me that it's just coming back full circle, with bad Shadows once again being shown how bad they really are.