It's all about balancing for skill. Lemme give you a scenario:

Let's say player A has 12 million SP and is running full proto with Duvolle AR.

Her comes player B who has only 5 million SP and is running standard gear with a GEK-38.

Now, player A is in the complex and he just hacked the CRU. Uh-oh, he wasn't paying attention and player B turns the corner and they get into a gunfight. Dakka, dakka ensues and player B just dropped player A. What happened? Let's take a closer look.

Though player A had more than double the SP and superior tech than player B, player B had better aim and footwork. Player A thought he could win with superior tech, and tried to tank player A's GEK-38 while player B butterfly strafed player B's Duvolle. SP and gear matters, but at the end of the day, a player with a better gun game and footwork still has a better chance of beating a player with superior tech if their aim is weaker. But let's go even deeper:

Lets say player A is running standard Amaar assault with 400HP and an Imperial Scrambler Rifle.

Player B is running Caldari Logi with 700HP and a GLU-5 Tactical Assault Rifle.

Same scenario, dakka, dakka... but what's this? Player B was the one who got dropped. What happened? Let's take a closer look.

This time, even though player B was running superior tech, had better aim, and had more EHP, player A was specificially geared to handle him. Player B was shield tanking in a Caldari suit and the Emperial Scrambler Rifle player A was using cut through his shields like a hot knife though butter, leaving player B with only a fraction of his HP and was easily dispatched because player A had a better fitting despite its average meta level being inferior to player B. Let's do one more

Player A is a Caldari assault CK.0 with 4 damage modifiers and a Duvolle.

Player B is an Amarr MK.0 with an imperial Scrambler rifle.

Same scenario dak- wow, that was quick, player B died before I could say dakka once. Let's take a closer look.

Even though player B was fitted with player A's effective counter and had better aim, player A has better reflexes and is more of a twitch shooter player, so he was smart enough to fit himself for ganking.

My point is that there are different types of player skills being merged together in Dust 514. Strafe and track FPS skills, twitch FPS skills, and meta gaming skills. SP is going to somewhat help each type of skilled player, but SP will never be "I win button." Skill, experience, tactics, and knowledge are king, SP is the court magician that baffles and amuses with his illusions. Whatever particular gaming specialty you favor, you should always fit yourself accordingly to match your playing style.

If you're a twitch shooter with good reflexes, fit yourself to gank, using stacked damage mods and a high DPS weapon.

If you're a duck and cover, strafe and track kind of player, fit youself to tank with armor and extenders relative to your suit class's specialty.

If you're good with meta gaming, find out what the current fit of the month is, and fit your self accordingly to counter.

The SP matters, but to the extent of how far you can customize your character to your play style. There's a lot of meta gaming and counter play. People tend to forget that Dust 514 isn't just an FPS or just an MMO. CCP has combined the genres, with one genre reinforcing the other. Play to your strengths and say **** the SP.