I play KOW too and haven't looked back to what is currently happening at GW (AOS) for the last year and a half or so. I have to say I am very happy with the system and I also use it to play historicals with it too. The only gripe is that I did not find a way to fit in my warrior priests other than as generic heroes but other than that, I am happy.
If you want to play a sigmarite army, or any kind of fanatic/religious human faction, then basilea is the obvious choice, eitheir as your main list with maybe some KoM or League of Rhordia allies, or themselves as a small allied detachment.
Warrior priests can then be represented by priests (note the CS(1) marking them as somewhat fighter despite having only one attack), or if you want your priests more in the warrior categorie, as high paladins (heal slightly less powerful but much better combat profile)
Note that Normal priests inspire penitents (flaggellants), and high paladins (arch-lector or powerful priests like luthor huss or maybe Valten) have a global inspiring.
A pure basilea army (without the angels) would make a fairly good religious baron going on a withc hunt with the help of some warrior priest/withc hunters. And if you want some angles, then the winged sigmarines from the AoS starter box will be perfect.
If you prefet use the KoM with some noce warrior priest that you have without needed to go the allies route, then another easy and perfect way to field a warrior priest is by giving the healing charm artefact to any appropriate hero, usually a simple army standard will do, but a general can also be great is you want the fighting abilities. A hero might also be another option, but he lacks inspiring, and for a priest this seems like something that you should have.
Also, some additionnal ideas for a heavily religious force :
- army standard or hero with war bow of kaba : witch hunter with rifle
- army standard or hero with flying hammer : witch hunter with pistol
(take the "Hero" hero, the one with a fighting profile and no inspiring if you want to get close, or the army standard if you want a rabble rouser that snipe)
About magic, I find it very good, the different spells already cover most spells archetypes :
- long range precision shooting (lightning bolt)
- short range area damage (fireball)
- healing/raising the deads (heal)
- moving your own units (surge)
- moving ennemy units (wind blast)
- buffing your offensive power (bane chant)
Also note that each spells has a level that is the number of dice that you use when casting them, so an elven wizard with lightning bolt(5) or fireball(10) will feel much more powerful than a goblin caster with lightning bolt (3), and not all casters get access to the same list of spells nor the same level (your elven wizard is powerful, but expensive and you don't get the option to pay for a cheaper lightning bolt). Also, wizards usually start with one default spell, and as you usually don't want too many spells on the same caster as you can only use one per turn, this mean that this simple default spell already make wizards with a similar spell access very different.
For exemple the elven wizard starts with heal as default, while the twilight kin (dark elves) version starts with fireball. Both have in theory the same spells at a similar cost, but this simple difference make elven wizards much more defensives and heal much more rare on twilight kin.
With magic spells working like ranged attacks, they are nicely integrated to the game and not a separate subsystem, also you pay for the spells you want, no random selection, so your wizards are costed an appropriate number of points, they are very nice to have, but if you want an army without any you can (I would however not recommand an undead army without at least one surge source unless you really know what you are doing).
In any case, you wont delete an undamaged horde with just one casting of a spell, but you might use a spell to finish a damaged one, or to snipe an army standard, or to kill a chaff unit that was coming your way.
Also support spells like bane chant or surge can be game changers if used correctly, surge can give you trick charges, and bane chant on a unit with lots of attacks or shots can make a great difference to the resulting damage, especially against units with a very high defense.
About tournament tweaks, the current list (not officially final yet, but already used by some tournaments, including ETC) is from memory something like this :
- allies cannot take artefacts
- units lose flying while disordered (so you can try to pin a flier after the initial charge top prevent it from fleing too easily)
- both pharahos have their def reduced to 5+ (they were too good for their points)
- In dominate and invade scenarios, units with the individual rule are only worth half victory points (to prevent abuse by small but very expensive and very mobile heros like mounted vampire that wait until the last turn to rush the scoring area). Big fliers were also sometimes a problem there, but with the change to fly above they should already be fixed
- In loot scenario (the one with moveable objective counters), you lose fly and nimble rules while you are carrying an objective in addition to having your speed capped to 5 (this prevent a specific situation where an army with some fast units that get first turn might win by turn 2 against some slower armies)
I might have forgotten something, but this should give a good general idea of the changes.
Finally, about general tactica, see the similar thread on the official forums :
http://vb.manticforum.com/forum/kings-of-war/kingdoms-of-man/280820-general-army-advice(especially my answer in post #5 to give an idea)
You can make an human army works in very different wayts, I have someone making a roman like army with almost all infantry with some ranged support and limited cavalry, but also all cavalry armies (tricky to manage, but can work).
i would advise that you start with a nice balanced army to get a feel with all unit types and tactics and only then thing about specialising if you still want.
Just one final word of advice : the simple number of units is very important in KoW, a common error for players coming from warhammer is to take the most elite unit possible, with as many artefact you can pay for to make them even more effective. While this kind of army can seem strong at first, especially if you play against a similar minded opponent, against a more experienced player with a balanced army you will usually find yourself outdeployed, flanked, and then killed, elite units are better used when they have other units to protect their flanks or otherwise fight one versus one, but if you fight one versus 3, say goodbye to your elite. That why if you take some expensive units like big elite hordes or monsters, it's usually a good idea to also compensate by taking some cheap unit and/or hero so you don't fall too much being in total number of units.
Usually for 2000 points you might want to have something in the 10-14 unit range, most often 11-13.
You can use
http://kow2.easyarmy.com to try to make an army to give you an idea if you want.