So with the Minstrel rework on Bullroarer, it seems clear now that the future of LOTRO is classes having two specializations and one "passive" tree. Which is going to be controversial, inevitably, but it does seem like a sensible choice given that most classes barely have one viable spec, let alone three...
I think I'm going to make the case that, when this change comes around to the Captain, it's red line that should go. That might seem counter-intuitive, since blue line is unfashionable at the moment while red and yellow are mostly coherent and in-demand, but here's the argument: A) Captain has never filled a "DPS" role in groups, so a DPS specialization doesn't make conceptual sense, and B) Shadow's Lament would become a core class skill, or at least one that blue and yellow Captains could trivially invest in, which would fill out the rotations of other specs, especially Yellow.
The big question marks are Blade-Brother and Relentless Attack: let's be honest, these are the primary appeal of red line, and if you gave either of the other specs access to them they'd never use their own unique versions. So what to do? For Relentless Attack, I would propose removing the Outgoing Healing buff and then making it a core Captain skill. For Focus and On Guard, simply move their triggers from using Sure Strike while Battle-Readied to using Sure Strike while Battle-Hardened. Blade-Brother is trickier. To Arms, Inspire and the -Brother buff itself provide the same stats in different proportions... perhaps it's time to simply condense them all back into one skill. Instead, move the distinction between Blade, Shield, and Song onto the Call skills, which are the ones with a clear identity between the lines anyway. Let us get multiple Call skills via traits and make them mutually exclusive on a shared cooldown, so we have some tactical choice -- 90% of the time the correct choice will be to use Blade-Brother over the spec versions, but it's still more choice than we get now.
Since our "specialized" DPS was never special enough to fill a DPS slot (as opposed to the dedicated "Captain" slot that we happened to be in red line while filling), it makes more sense to move our group buff DPS to core skills while letting our other specs opt in to supplementing their personal DPS via the new "passive" red line. Why not de-specialise either Blue or Yellow instead? Simple: Yellow, while the traits themselves are a bit of a mess, is a valid group role that we successfully fill right now, while Blue, if it became passive, simply wouldn't be used any more apart from one or two particularly good traits like Blood of Numenor, Revealing Mark, and Courageous Convocation.
Anyway, I'm obviously not (and shouldn't be) in charge of anything, but I just wanted to provide a little food for thought.
Cainwen Ciaphas, Captain of Crickhollow, HERO OF MIDDLE EARTH!!!
I will not be pushed, filed, stamped, indexed, briefed, debriefed, or numbered! My opinions are my own!