First your paladin is level 80 vs the rest of your team being 70. You paladin should not have any issues landing spells and attacks on the grey/barely green mobs in UK, whereas the rest of your team in BC blues. They are going to have tons of resists and misses compared to your paladin.

Second, Warlocks and druids get a decent chunk of DPS from DoTs. If the mobs aren't lasting long enough for DoTs to run to full, you're not going to see decent DPS compared to a paladin.

Third, paladins get a TON of DPS from AOE. I recall many times where my husband outDPSed real players simply because of consecrate and shield spikes and all that random tanky stuff in high-trash instances.

So yeah, your paladin is seriously going to outDPS your team until your guys are in proper Northrend gear with something along the lines of appropriate Spellpower and Hit and in a fully level-appropraite dungeon.