Warder and Spells Strategy (level 50-54)
At 50, you get one new spell: Sha's Lethargy, a 30% slow. This is a noticeable upgrade to Drowsy, and won't be upgraded until level 60. A wonderful spell.
For level 51, you get two minor spells, Ultravision and Resist Disease, plus Spirit of Wind. Spirit of Wind is a new pet buff, which includes a 0 second stun, and a knockback. The knockback is annoying, but it is very effective in interrupting casters. This pet proc makes killing dryads in Jaggedpine Forest almost trivial.
Level 52 gives you Heath (sta buff), Venom of the Snake (a dot, from the necro vendors in Plane of Knowledge), Aid of Khurenz (pet heal), Spiritual Radiance (upgrade to Spiritual Light) and Bond of the Wild, quested in Gunthak. At this level, I still used my level 39 pet heal, because it is very much faster casting, and more mana efficient as it benefits from spell haste and mana preservation level II effects. Bond of the Wild is also very important for several more levels, as it combines the effects of a pet haste buff with an exact same hit points buff for yourself as you get with Talisman of Tnarg (a level 53 spell). Venom of the Snake is important, as it does 453 damage for 160 mana over 7 ticks, which means that it will complete over the duration of most fights, and is almost (but not quite) as mana efficient as the PoP nukes.
At level 53, you get Talisman of Tnarg (hit points buff), Deftness (dexterity), and Spirit of the Storm (pet proc). I didn't use the Talisman at all, except to buff other people, until it's replacement at 58, Talisman of Altuna. Spirit of the Storm is the last easy to get pet proc before the 60s; it stuns for a brief duration, and seems to interrupt casters just as much as Spirit of the Wind did.
So far, you are still using the level 49 warder, with slightly better buffs, including pet procs/haste and regen. At 52, you'll find that the old rule of 1% experience per mob killed no longer holds true, and each level will start to take a lot longer. With luck, KEI and steady application, you'll be able to get a level in 6 to 8 hours in good hunting spots.