You cite a situation where the fighter is getting four attacks. That means high level. The amount of high level foes that don't have SR is limited in my experience (other than NPCs, and even they can get it). There's your roll to hit for the mage. This is, of course, coupled with a saving throw. Given that almost every spell is now damage with a save, or to hit for damage, that would also ameliorate your issue. There's almost nothing left of the save or die variety. There's still a bit of save or suck, but that's it and a lot of those allow continuous attempts to save.
Fighters got a rather nice feat chain called vital strike. This lets them do significantly higher damage at the expense of iterative attacks.
Here's the top end from the PRD:
Greater Vital Strike (Combat)
You can make a single attack that deals incredible damage.
Prerequisites: Improved Vital Strike, Vital Strike, base attack bonus +16.
Benefit: When you use the attack action, you can make one attack at your highest base attack bonus that deals additional damage. Roll the damage dice for the attack four times and add the results together, but do not multiply damage bonuses from Strength, weapon abilities (such as flaming), or precision-based damage (such as sneak attack). This bonus damage is not multiplied on a critical hit (although other damage bonuses are multiplied normally).
There is also:
Deadly Stroke (Combat)
With a well-placed strike, you can bring a swift and painful end to most foes.
Prerequisites: Dazzling Display, Greater Weapon Focus, Shatter Defenses, Weapon Focus, proficiency with the selected weapon, base attack bonus +11.
Benefit: As a standard action, make a single attack with the weapon for which you have Greater Weapon Focus against a stunned or flat-footed opponent. If you hit, you deal double the normal damage and the target takes 1 point of Constitution bleed (see Conditions). The additional damage and bleed is not multiplied on a critical hit.
Which follows on from another couple feats in the chain which render the target flat footed until the end of your next round.
So these feat chains, coupled with the extra +5 to hit you will be getting at the high end means a serious damage increase for the fighter. There are also feats which put riders on your crits, and allow you to really hash up spellcasters who are trying to cast defensively. Include in the lunge (which increases your reach), and Step Up(which allows you to take a 5' move with your enemy as an immediate action if he does one to step back) and melee people with the right stuff will be playing hell with casters who don't know to keep their distance. No more "I step back 5' and cast".
You can look over the rules yourself since they are available in the PRD
That was an excellent answer. Cookies for you.
I am now going over the PRD and will be adding PF to my shelves.
