Just a couple of ideas, from my experience running a couple of lowbie quests with total newbies (newbies, not noobs) recently.
1) Newbies are often frustrated that they can't seem to contribute due to the level of twinking amongst experienced players they PUG with. It's humiliating to the newbie Barbarian to find that they are doing less damage in melee than the highly twinked bard with the ML2, RR +1 acid rapier of pure good (not to mention when they encounter someone with a ML2 Maelstrom, RR +3 Mithril Fullplate and a stack of Heroism, Barkskin and Haste potions so large they need an entire inventory tab for them)
Proposed Solution:
First, add some +1 energy weapons as bound end rewards to the most popular lowbie quest chains (perhaps a +1 flaming sickle to Waterworks, a +1 greatsword of pure good to Tangleroot, a +1 acid battleaxe to STK, a +1 holy handwraps to Delara's and a +1 frost rapier to the Catacombs). New players will appreciate it, and it will help them close the gap on twinkers, experienced players will not notice it at all.
Secondly, award more potions of useful spells as end rewards for low-level quests - particularly useful potions newbies can't really afford to buy themselves like Heroism, Haste and Barkskin, plus the essentials (Curse Removal, Blindness Removal, et al). In particular, I'd change the quests in the Harbor that currently award a small amount of GP as an end reward to instead award three or five of these potions.
2) STK is a quest many newbies get frustrated with. Parts 1 and 2 are perfectly balanced, just the right difficulty that a level 4 party with no foreknowledge and no twinking will tromp through part 1 with ease and beat part 2 but find it a challenge in parts.
Part 3 is ridiculous, however, due to two encounters which will almost always wipe a level 5 party with no foreknowledge of the quest: the fire trap room, and the final boss. (I've known a player, in fact the person who first told me about DDO before it was released, that chose not to upgrade their trial of the game after being frustrated by these encounters and thinking that the whole game would be like that). Even experienced players almost always choose to use tactics that exploit weak AI rather than fight the Guardian straight up - as straight-up, he's tough even for a twinked level 5 party on normal, and two untimely crits could see such a party get wiped.
Suggestions:
1) Add some warnings about the fire trap room to Wayfinder Dael's initial dialogue when she gives the quest. Perhaps have her say that the Seal of Shan-to-Kar was forged in a fiery inferno inside the Halls, and that no record of this fiery forge being destroyed has ever been made - and that the players should take something to provide magical protection from fire before they undertake their quest, as it may take them through this forge.
2) On normal only, reduce the DR on the Guardian of Shan-to-Kar to 5/adamantine, reduce his AC to something newbies can hit without needing a lucky roll, and remove his ability to land a critical hit at all. Keep him exactly as he currently is on hard and elite - newbies usually have a level of respect for those settings that we veterans don't have.
3) Reduce the base XP of STK part 3 by 5% to compensate for the quest being easier.