Spoiler:
It is the single easiest/quickest possible fix to make melee healing viable on the DoK. There are a lot of great proposals and this change would be able to work ALONG SIDE them in that you have to swap a VERY useful tactic to get this. Other changes mention empowered transfer - which in theory should be ran in the melee healing spec - so this change would only work with future changes, not against them - and again.. it is quick, easy, to the point and doesn't make the dok any better at damage (people hate that) but actually less damage but more healing (people would most likely be okay with that).
Spoiler:
Melee healing on the DoK is the lackluster version of the DD spec. You either don't get the HD (pending your RR rank) and if you do, you don't get pillage essence (unbelievably good for soul essence but not spec'd into as much since Wracking Agony is usually taken in its place the majority of the time (yes, 1 or 2 doks run PE over WA but the vast majority do not do that). So the entire purpose of the right tree is for melee healing, this would allow you take TE in the place of AA haste or HD pending what you choose normally when you have empowered transfer on - therefore effectively decreasing your damage, but increasing your healing allowing you to actually fulfill the role as a melee healer which you currently are not able to do.
Spoiler:
Simply because the other changes while they seem very good (some are) - would take a LOT more work. This change could supplement the other changes and be a sort of "get your feet wet" step in the direction of being able to actually play a melee healer well. As stated above - it would only supplement other future tweaks to the melee healing while not making the DD spec any better (people like DD DoK where it is because it doesn't just murder everyone now).
Why not for WP?
Spoiler:
WP melee healing is actually not in a terrible place with their 2h granting much larger lifetaps with their tactic, as well as the wounds buff being able to be used as a backline AOE heal.
Spoiler:
Currently, melee DD on a DoK is viable pending a few circumstances. Similar to choppa. You need a guard that can float, for sure at least 1, preferably two other healers - so you can focus on actual DD'ing. HOWEVER - melee healing is lackluster with no good backline heal like the WP's wounds buff, and also significantly less life taps with the fact that we use a 1h and not a 2h.
Spoiler:
Currently the tactic on landing a critical melee strikes grants your defensive target 20% increased healing via direct heals. This is somehow considered by mythic to be equal/counter/dokversion of the WP "On defense (ie. parry/dodge/disrupt) - your direct healing is increased by 20%" - Not to digress too much but this tactic just shows how they intended the class to cast heals while also being in melee range. I think it fails because it is just 1 target, instead of all targets, and also because you aren't going to be able to stack crit heals and crit damage effectively with all your other stats being so hard to get as well (problem with dok/wp's melee healing) So if this tactic was changed - it would allow 20% more effective melee healing ie. lifetaps at the sacrifice of either AA's or heal debuff - since you'd still want to use empowered transfer otherwise you are just DD and not melee heals in the first place...
Spoiler:
a 20% increase to lifetaps would basically just put each life tap on par with the WP lifetaps, 20% is not going to make it OP, but it would make it somewhat viable. if 20% is too low, other options can be taken into consideration granted with TE you lifetap around 700-900 pending squishieness/debuffedness and so on.