Well I woke up earlier than i should have, got bored, so I'm deciding to finally post something on forums. These are just a few tips I got from legendary compaign solo (I dont have live so it kept me busy for a good like 9 hours).
Wraiths are really evil, with amazing aim..., so you should try to headshot the turret gunner and then do some amazing sprint action to jack it, plus it saves you a bunch of time since the wraith's blast is epic.
It's legendary, so no hard feelings to the enemies (elites preferrably) if you stumble upon the noob combo of dmr/needle rife and plasma pistol. It is a life saver, especially in pillar of autumn, idk how I woulda done it without the plasma pistol (and the secret ammo bin thats stuck in the wall).
Take your time with enemies, don't rush through or randomly shoot, line up your shot to the head and get it done, it's gonna take time, but it'll save you time instead of dieing like 15 times. And take the smaller enemies out first, they always seem to get away and start shooting you relentlessly while youre trying to get the bigger ones.
If you're with noble team, have them go out first. they dont die so they can get some (or most) of the job done and you can come in with a quick headshot.
Hunters are fairly easy, even in the one with the 2 in the sword base (sprint into them, and draw one outside, so you can deal with one while the other is unable to shoot you). Just grab a shotty, or any gun for that matter, and just run circles around it. it will constantly try to do that reverse smash if you are close enough, and it has some delay time, so just fire at its open back.
Unless you are in a tank/wraith/thingie thats like a wraith/ghost combo, I wouldn't get into a vehicle. They are just big targets and the AI that is either driving or gunning sucks. So just use them for transportation, get out, headshot some dudes, then drive off.
Sword is better than shotty, try to find one the hold onto it. It's not a bad idea to hold whatever button you use to pickup weapons, then get 3rd weapon, and alternate picking up and running with them so you can have a 3rd power weapon incase of a sticky situation (I do this with rockets or a sniper).
Armor lock is a life saver. Emile is practically useless. If a detachable turret is lying around, go grab it. Try to get those BoBs and switches. On the package, run through most of the stuff and while defending that chicks lab, get a jet pack and jack a banshee (it's really easy, they are everywhere. It was a piece of cake after that. and take out ghosts, they drill through you). Luring is a good tactic, use it if you can. Try to assassinate as many elites as you can in the covanent ship level, and let the invisible elite draw it's sword out before killing it.
Sorry all that it was kinda long and boring, I just poured my thoughts as I was thinking about it. Hope it helps.