My problem is that i think warriors dont do much and there are to many of them so thats why i was looking for something more "elite". So maybe better go knights then...? Or what do you suggest?

Thanks for all the tips so far! Great info!
Dont know alloy about other army's...yet
first thing to know: warriors are better than guards if you plan to throw big units in melee, accepting heavy losses but dealing good damage in return, while other heroes add their weight in the combat (sunblood, Carnosar and similar)
In defensive combat and employing smaller units, guards are better, hands down.
However, as said you must be aware that certain enemy units are a bane for elite troops as guards, so you must "protect" your points investment. This can be done in many ways:
avoid unwanted charges: you are slow, so the enemy can charge you easily. Surround your 2 "ranks" of 10 guards with a thin screen of 10 disposable, cheap skinks. If something wants to charge, it must clean your skinks before, or it will impact on your screen, without dealing damage to guards, that will be dragged in combat with "pile in".
Protect from shooting: increase your saves with magic or, even better, use Starlight to impose a -1 to hit to enemy units targetting the guards. This will work also in CC, to reduce the chances to be the victim of nasty effects (for example: bloodletters of Khorne inflicts a mortal woundsfor each 6+ to hit; if you reduce their to hit, you will be protected from one of your worst enemies: mortal wounds)
Scare your enemy: make your guards a truly fearsome threat in close combat, something the opponent will forever try to escape. This works really well with mixed armies (a combo of guards / mystic shield / eternity warden / Sisters of the thorn is devastating. Read the description of the spell of the sisters and smile), but can be done also with seraphon only units (keep your 15 guards in the range of 4 salamanders)
This is not perfect, there will always be something that will laugh at your tries and will just blast away your precious guards (dwarfs flame cannon, just to name one), but you will learn to know those threats, and will deal previously with them (shadowstrike starhost and / or chama skinks)