Nostalrius Begins - Quality wow vanilla realm (1.12)

Just want to ask one question, first time playing vanilla. Going to try warlock, check out this build.
Is it good for leveling and maybe a bit world pvp? -
http://db.vanillagaming.org/?talent#IA0bVRbkAZfLZxxb

Drop the Improved Firebolt since it's the one pet you won't use in combat. The only use for that talent is with the Black Book trinket which turns your imp into a machinegun of fireballs for a few seconds until he runs out of mana. Not something to build a spec around unless you just want to have some fun for a while.

Shadowburn is really important for both leveling and world pvp, even raiding it's a great spell to use when on the move or things get killed too fast.

Suppression is not that viable either. For leveling you really need to get the Improved Voidwalker asap. As with many classes it might be worth to level as one spec up to 30-40 and then when world pvp becomes a factor, switch to a more pvp oriented build.