Taunt , Challenge and tactics - Is there wasted potential?

So I've always thought that two of the four class defining abilities that tanks have (challenge and taunt) have no actual interaction with any other tactics or abilities. The tactics in that mastery can be good but especially as a Black Orc the top tier tanking tactic is absolutely rubbish (you can check previous rants on it in older posts). I'm sure each tanking class has the same issue, a tactic in there that really, isn't all that good and would rarely if ever be slotted and you'd gladly see another one replace it.

I have a little proposal for all tanks, it's not overly thought through so potentially it might be a bit potent or underwhelming but how about this for the top tier tactic in your tanking tree:

1 Slot Career Tactic - No range - No cool down - Passive
(insert name here)
Cool down on Taunt and Challenge is reduced by 5 seconds and the effectiveness is increased by 5%

So this would put Taunt on a 10 second cool down with 35% extra damage and Challenge on a 25 second cool down with enemies doing 65% damage to all other targets. The question is, would it become an option for you to slot, something to ignore or an essential tactic?

There's other possibilities as well, such as increased range or making Taunt a cone effect like challenge. Could we also then do things with Hold the Line?