Eh, I’m bored as all get out, I’ll give you my take on the run down. This will mainly be from the viewpoint of team games since that is what I've played most.
Leader: opening1,2 - mid3,4 - late5,6 - end6+. Notes
Cutter: Awesome-Awesome-OK-Worst. Very solid opener given that his infantry are the fastest around or in interesting scenarios can be fueled in veterancy from spam players like yap yap. Mainly going to be speccing in infantry to be taking advantage of this characteristic. ODST allow him to have one of the best on punches in mid game crippling multiple important structures of your opponent and combining for a one two punch with archer missiles. Unfortunately he is hands down the worst endgame. Keep in mind (people that are triggered) I would like to super turtle triple Cutter. If he is not the one killing, he is the one getting killed (Skidda nominated for Nobel). His powers and reinforcements are good, but overall pale in comparison to the strengths of other leader powers. 12 o'clock end game can get shot down... He pairs well with other aggressive banished (Atriox, Voridus, Decimus) with sniper support to quickly shut the opponent out.
Anders: Good - Maybe Best - Awesome - Good. Functions very similarly to Cutter but for different reasons to spec into infantry. Cheap upgrades, that is all. In general specialized infantry is very yellow intensive to make and make good. Having half price upgrades global and relative is sweet. This is what makes her mid game so good is because you don't have to think twice about buying a 2nd global upgrade for whatever you are building before hitting tech 3. Overall her late game is sweet and really convenient on divided maps like sentry where her ultra sentinel can be a pain in the butt if not challenged by opposing air units. Unfortunately her 6 o'clock doesn't scale well against units as combat progresses and end game becomes only turtler. Pairs well with just about anyone, and has a nomination for super turtling.
Isabel: Strange-OK-Fantastic-Best. I have bias on this one so I will try to stay objective. I can't rate her opening bad because its not, its just way different than any other style. Holograms are the only real choice for lp one right now and their usage is for the creative (run them into mines, or nearly turrets, etc). There are those that claim she is best to go just straight into hogs to take advantage of acc assem, and to be honest there are uses for this capability. If you can survive and flourish enough mid game, her passives and godly end game powers begin to truly shine. She builds the cheapest and most powerful tanks... which is more important than its ever been. Having double assembly and the ability to turn enemy vehicles on a click makes her my number one for end game play any day. Pairs well with anyone who can help carry the opening.
Atriox: Best-Great-Great-Great. This won't shock most people, but new guys don't quite understand just how good Atriox's passives are early game. Want to enhance one of the heaviest hitting building killers to make them more offensive and at the same time insure your node captures, check. Want to be able to second base like a champ and suffocate your opponent under your 7 bases late game, check. If unchecked his leader the chosen outputs the highest damage a banished leader can bring, ultimately giving him the best chance to shut an opponent out early game. His powers are geared for invincibility and my favorite powers are geared for just that. Most people grab the beam for its current strength, but considering its lp 4 you should consider more often than not teleport so the you can dodge those enemy leader powers. Overall a very consistent choice. Pairs best UNSC for additional sniper support since he can manhandle banished with his leader and brutes.
Decimus: Awesome, good, Great, Fantastic. Mr Combo Mombo, the leader sniper incarnate. If you know what you are doing with the warlord, that big brute is any leaders worst nightmare. Take the time to practice y ability on dragged units in an effort to insta kill with grunt mines and vortex. Early game is only strong on the ability to wax your opponents best units early. If unable, then you are in for a rough opening game. I will say vortex siphon should always be your choice unless against yap where you should consider killing frenzy over vortex. Mid game is propelled by the beam option. Late game is where he gets awesome passives and the most tanky leader(s) in the game. Considering all the powers on his wheel, it feels like he only gets stronger as the game progresses. Pairs well with any aggressive leaders or for 6oclocks plus vortex. (Vortex reign of fire is insidious, for example)
Shipmaster: Bad-Great-Awesome-Awesome. This slippery dude. I have to say is opening is bad, and that is only by comparison to what other leaders can do. Its also because his leader is the most prone to doing something stupid (like a finishing move) and getting himself killed. Now there is the caveat that if there is no detect unit on the field, then the honor guard is god. However, most UNSC have the intuition to ball up enough snipers and marines to make him a non issue. Pretty much this leader can only 'survive' tech 1 play or tele cheese with some brutes. Ghosts and suicide grunts and teleport, it is your job to figure out how to make that best work (because it does work, despite the tone I am starting with). Once your third leader point comes around and you have tech 2, all changes. Suddenly you have the best ranged elites and hunters and already have teleport for some high level locust play (teleport and extraction is so sexy I'm pretty sure its blocked on youtube). As the game progresses you get the most tactical leader points that could ever be granted. Displacement and gateway on top of teleport and extraction makes for a leader that directly controls everyones position, the makings for a chess players dream. Pairs well with any strong opener
Let me know if you want more than just the scrappy six, and also congrats for actually reading all of this.