Please don't turn this into a flame or go off topic, because I think this is a very important thing for the developers to see. And also important for the players who don't understand that its possible to build anti-spellcaster builds with the items and stuff available in game.
-------------------------------------------------------------------
The first thing I'd like to say is that I'm writing this because I consistently am able to beat up spellcasters with my fighter build... And my sorcerer and cleric (both over level 20+) are consistently beaten up by other people's fighter builds who have learned how to make good NS4 builds. This says to me that spellcasters are overnerfed. The development team however continues to nerf spellcasters.
Having played some PnP D&D and also reading some forgotten realms books I know that wizards and spellcasters are supposed to be able to beat up a single fighter. It usually takes a group effort to take down a spellcaster, and often requires tactics.
When I'm able to run up to a spellcaster in NS4, and simply attack him and he can't do anything but run away there is a problem. The fighters have many weapons to go up against the spellcasters
1) Knockdown
2) Concentration checks
I am able to consistently beat spellcasters on both fronts.
I hear people complain and say, well a spellcaster has premonition and stoneskin etc etc, but the sad fact is that spellcasters don't have AC, and last but not least spellcasters can get immunes/resists to only 2 of 3 things. Those two things are typically piercing and slashing. Anyone going up against a spellcaster with a weapon that deals slashing is an idiot.
It doesn't matter if you didn't get weapon focus in a bludgeoning weapon, it doesn't matter if you didn't get improved crit. The fact is your bludgeoning weapon will go through the spellcaster like a hot knife through butter.
Take this build for example, a weaponmaster(7)/fighter(9)/bard(4)
And after level 20 I'm probably going to put one more level in fighter (to get epic weapon spec) the rest in bard so it'll wind up with 23 levels of bard probably
you can't get max str in this build because you need enough charisma to cast bard spells, you need enough dexterity and str for weapon master, and you need intelligence for skill points. But this isn't so bad because you should get 10 or over in each attribute so you don't get hurt so badly on your saving throws anyway.
If you take weaponmaster in warhammer, you will have a decent crit range and an x4 multiplier with a bludgeoning weapon. Or if you want to build a supreme mage killer you can go weapon master heavy flail and use a shield when you're not fighting a mage. The heavy flail is a very nasty weapon to use against mages, and if you go weapon master in it you'll be close to unstoppable when a mage comes by if you're prepared for him.
So what does this build get for you? It gets you a fighter build (with a couple less strength than a pure fighter) it gets you taunt skill, tumble, bard song, curse song... Gives you a bludgeoning weapon with a large multiplier that will eat through premonition and greater stoneskin, the fighter will get you weapon spec and epic weapon spec (total of +6 damage), knockdown and ability to cast spell scrolls and level 6 arcane spells eventually (in epic levels as bard). You can take still spell which will allow you to cast arcane spells in armor (stuff like haste and other bard buffs).
How do I kill spellcasters when I run into them?
First thing I do is chug a potion of lesser spell mantle, then I activate my drow shadow armor (which gives me shadow shield). Then I use a breach or mord scroll on the spellcaster. Run into his face and knock him down. They never come back up.
-----------------------------------------------------------------------------------
Now I know the devs have read up to this point and are going...
Hrmm hrmm powergamer hrmm...
Ok, so lets take a level 20 paladin as our next example.
Paladins get a very nasty spell called holy weapon. This makes your weapon +5 and renders premonition and stoneskin useless (since they can only absorb +4 weapons). Paladins also get a spell called divine favor (which will give +5 magical damage and +5AB at level 15) and a bunch of other very nice feats and spells (divine might/shield for example).
So a paladin with a good charisma (say 20 with gear, 15 base charisma) will be able to add 5 divine damage, and 5 magic damage with divine might and divine favor. The paladin can take their warhammer or heavy flail and make it a +5 weapon with holy weapon. Now a sorc only has their resist and immunes on their armor and since its a bludgeoning weapon 95% chance says the sorc doesn't have any bludgeoning resist/immune. Chug a potion of lesser spell mantle and into the fight you go.
In fact, you don't even really need the lesser spell mantle potion because you have lots of saving throws +5 from your charisma bonus. If you were smart you woudl have also taken the reflex feat and are wearing those silly god for awful boots with +5 reflex on them. Oh and I forgot the potion that gives eagles splendour for another 3-4 charisma (even more bonus to saving throws).
The sorc can't instant kill you... and you will save on the sorcs spells and take moderate amounts of damage. If the sorc doesn't run, he's a goner.
and finally...
the pure monk...
A pure monk has improved movement speed (enough to make him blazing fast at level 20). He has high saves across the board, high AC, and evasion. I've been killed on my spellcaster so many times by pure monks its almost absurd.
So please please please development team. Stop focusing on nerfing spellcasters. In fact, I believe spellcasters should be beefed... Cleric spells deal hardly any damage, and they are reduced to death magic and beefing themselves and summons and attacking. Hardly such a thing as a caster cleric any more.
There is no point in many cleric spells now. Durations have all been reduced... Why bother with blade barrier when it lasts 5 rounds at level 20... Why bother with word of faith when it lasts 5 rounds at level 20 (ever hear of remove blind or restoration potions... Why are these in the game again?). Why bother with anything? Might as well just cast level 2 buff spells and attack. Follow any level 20 cleric and thats exactly what they do.
Its not the spellcasters fault that everyone is stuck on making maximum strength half orc barbarians with longsword as their weapon and then they come to complain.

----------------------------------------------------------------
Lets see how else can we beat spellcasters... Most don't have high str... So anything that does str ability drain is sure to hurt alot....
Crippling strike
Negative Energy Burst
Weapons with fortitude saves hurt ALOT. Especially the ones that drain levels... Sheesh, my mage got hit by one of those the other day, like 5 times. The fighter laughed at me when I died not from loss of HP, but because I went to level 0.
These are just some ideas to make the community aware. And hopefully the devs have enough insight that they can see their nerfing of spellcasters has gone too far.
[~]