That's like asking for Chayesh's picture. It's an enigma.
Weapon Expertise / Mastery
I kinda lost faith in picking lores I had no idea about after the sword lore. Maybe I did something wrong, who knows, it just didn't seem useful at all. All that training and ranking was for nothing 
I've tried all of them over the years, and feign is the only one I've considered a poor choice. Maybe the real advantage was that there are quite a few decent swords and daggers out there, or maybe I was just missing something.
Great, leave it to me to pick the only one that sucks.
Wow, someone actually thinks that because I couldn't see a good use for a skill that it must suck 
There might be more to that skill than I ever figured out. I actually didn't spend all that much time trying to figure it out. The biggest drawback I saw with it was that so many classes know how to use swords (or daggers, if it still applies to both weapons). And it's already been stated that using a weapon your opponent can't learn is a tremendous edge for warriors. So in most fights I didn't even bother using a sword.
My impression of warrior lore is that it was added to give warriors a bit of flavor; it wasn't meant to be a make or break skill for a character. And I've found that to be true. I had fun with my sword warrior, and he was fairly successful, I think.
Viri always said warriors should pump Hit/DAm, unless they chose a certain lore, where they should just power pump Dam.
One thing that I have noticed is that the best masteries and expertises and lores are to take ones that are easy to acquire for your chosen race, align, and path you take.
Let me elaborate.
As a FG warrior it is best you consider the array of fire based weaponry available, as it will be deadly in your hands. No matter what path you take in regards to cabal ideas and such all of the decent fire weapons are a good plan.
As say, a Stormie Warrior, which by this time I know like the back of my hand because I have played so many I would say that both spears and swords are very good choices. With such it is immensely easy to get your hands on very good and pk'able weaponry of both kinds with such ease as even simple requests.
I would never once recommend taking axes unless you are a minotaur. Mainly because it is not very easy to re-eq axes at all no matter what you are.
As overlooked as they are, shield expertise and bash are both very viable choices, as just like the others no matter what you are it is easy to grab an acceptable shield.
Whip is a difficult choice as it only works well for certain races. It is easy to gain a set of whips for all races, but it may not be the best decision for yours.
The last thing to consider is which enemies you will be fighting most. If you're a Warmaster you're bound to be fighting a lot of mages, maybe flails (a few of which are easily accessable) are the best choice for you.
And lastly I go onto the cookie cutter, yes staff warriors. Staff is a more than viable choice for ALL warriors, hands down. There are always good staffs in the lands, and if not then go kill some mage who has the one you want. Staff is given the option of two grand lores, both of which can be very powerful. Which one you choose ought to be determined by your race. Giant? Go for door #1, anything else it is always a good idea to go for door #2.
There's my outlook on specialties for all warriors.
Axes are difficult to re-eq with?
Invokers, Shaman, Cleric, Necro with 3 travens, Battlemage. I don't see a reason to use flails against any of those mages except maybe invokers, but if you do you won't be able to charge unless you switch your primary shortly after initiating. Thoughts..?
I'll say it again--I really liked the flail lore. I used it at various times against all of the classes you mentioned, and it worked well.
You know, I think people spent too much time fretting over which lore to pick. My personal experience is that they don't matter all that much. They add a bit of variation to the class, thus making them more replayable.
Axes are difficult to re-eq with?
Invokers, Shaman, Cleric, Necro with 3 travens, Battlemage. I don't see a reason to use flails against any of those mages except maybe invokers, but if you do you won't be able to charge unless you switch your primary shortly after initiating. Thoughts..?
Flails vs invoker EVERY time. Most of the good axes are 2h so you can't dual them (unless mino). Flails on the other hand come in both varities if you know where to look.
Shaman - flail isn't good vs shield block. Need to change weapons to get through this (axe isn't good here either).
Cleric - if using 2h weapon, yes, flail/axe (maybe axe is more effective, maybe it isn't). If using shield, same as shaman.
Necro - maybe flails. I've done dual flails vs necro as a zerk, its VERY effective...
Battlemage - in my experience I didn't get as much milage out of dual flails here as I did a polearm. More of an outlast thing so polearm/staff/2h magic axe. I think Viri recommend magic staff or 2h axe.
L-A
The flail lore is also very useful against Invokers because the flail lore is very useful against those who have to input commands to deal damage as opposed to a melee class who will pump out damage every round of combat regardless.
Just as an aside though, did you use dual flails often against Necros as a Zerk? With mine, I always went with a no-disarm polearm for the defensive option against their zombies, but I never thought about trying to absolutely destroy the Necro with dual-wield high-offensive weaponry.
Dey
That's why there was a stream of ghosts heading to your pit.
Just as an aside though, did you use dual flails often against Necros as a Zerk? With mine, I always went with a no-disarm polearm for the defensive option against their zombies, but I never thought about trying to absolutely destroy the Necro with dual-wield high-offensive weaponry.
Dey
After I tried shield/spear, polearm (Steelfeather) and found there was no way to really beat the necro silly I went cursed flail primary/dual flail. Net result - one necro beaten to awful. One berserker in almost the same state. He was worse off than me though :-)
L-A
Hmm. Definately something to think about.
Dey
I guess eventually I will figure it out, but when fighting against someone with pets, and they use the pets to attack or rescue them. Do you try and finish off the pets, or retarget said person and try to work them over?
Any basic strategies?
If you can see definatly retarget a rescue. They get lagged for two-three rounds for ordering their pets to rescue. Follow that with a bash/bodyslam/trip and they cant do much for a while. If I am blind, I dont stick around to find out what happens if I stay and fight.
It really depends on the class, if you playing something with high melee output and their pets aren't sanced you should kill their pets, but try not to fight them too much while doing it. Just keep fleeing and re-attacking their pets, giving you a free six or so attacks on them. If you have decent equipment it should only take three (maybe four depending on equip) rounds to kill ranger pets. This is usually a tactic you would use to start out battles though, not wait until you've lost some health and they are using their pets to rescue.
However, if they are using their pets to rescue it usually means they can't handle/block your damage very well or they are low on health. So in these cases it can be useful to go directly for the kill. Its really just a judgment call based on the situation.
With necros I'm not sure it's a good idea to kill the pets first. Kinda hard to take that sort of pain for long.
If you have problems with necros...make a blm and deathweave. After awhile they'll stop attacking you because they're tired of getting hit by their zombies.
If you are killing the zombies of a necro while the necro is in the fight and you aren't a healer than you are just wasting your time.