I can understand the wish to encourage players to play different quests instead of farming the same over and over.
However, we need to look into WHY we farm quests over and over.
I can only speak for myself, but one reason is that some quests are easily accessible and others take a long time to get to. E. g. you need to walk quite a bit to get to the quests in the Menechtarun desert. Wizking is not too far into the area, but e. g. Chains of Flame and Offering of Blood take a long time getting to. Combine that with late entries into the group, new players who don't know where the quests are and you see that people are reluctant to run such quests. This can be fixed by having a person in the bar who can send you to the different quests in that area. This works so well for Ravenloft and other areas.
The XP you get from a quest is important to evaluate if it's worth the effort for the life you're doing. Right now there are more quests than what you need to get to 20 (or 30) so you will have to pick which you prefer. Some quests are more fun than others so you skip those that can be frustrating (lots of traps, group splitting mechanisms (E. g. Xorian Cipher), nasty monsters (Legendary Shroud flaggers) etc.).
In quests with many traps you might skip them if you're not lucky enough to get a trapper PC in the group. Heroic trapper hirelings are not free to purchase and the epic ones can't find any traps on elite++. Maybe you should offer free trapper hirelings who can find traps both on heroic and epic even on elite and low skull reaper.
Some quests have splitting mechanisms so they are much harder to short man. E. g. one of the Necro 1 quests and Xorian cipher need 4 people. Hirelings can be used for some, but still. The same with one Delera quest. Maybe it would be better to not have group splitting mandatory for quest completion.
Protection quests are particularly frustrating. It's not fun failing Let Sleeping Dust Lie just because a PC you accepted killed too many spiders. Coyle in Threnal was renowned for failing quests. The first quest in the Sharn chain in the Marketplace is just as frustrating if you have to short man. Change the protection quests where protecting the particular person is linked to an optional bonus and not quest completion.
Some quests are run because of favor regardless of how frustrating they are. The most typical favor quests are Coin Lords and House Kundarak for the inventory and bank space. Why not look at the favor rewards again and ensure all different ones give bonuses players would really want to have. Some bonuses are linked to just being useful for a small group of players like arrows / bolts. Add favor bonuses for all tiers that players can possibly reach.
I think a good way of dealing with favor is to grant small toon bonuses similar to what we get from past lives. E. g. bonuses to skills or stats. That would be a way for players with not many lives to boost their toon. The goal should be to let favor grinding be an easy alternative way for players to become a bit stronger. The people on the TR train will usually get to 20 asap and start over so they won't spend the time to get favor from many different sources. However, those who advance at a more casual rate and won't TR at the first opportunity might get bonuses via favor instead.
Maybe you can link some nice bonuses to players who get to the highest tier of a favor patron. Now you usually unlock a enhancement tree at the highest tier. That is needed just once. Maybe you in addition could get a character bonus you only have while you have the favor.
More quest areas should have saga rewards. It would be nice to have a saga in the Desert of Menechtarun, Necropolis, Vale, Amrath and even other places. There should be enough quests in these areas to award sagas.
I would also look into what you're offered as Saga rewards. Now you get skill tomes, XP, guild favor etc. Maybe you can offer a random stat tome as reward for true elite? Maybe reaper XP or Sentient XP? Make the variety bigger so players can use Saga collecting as a way to build power to their toon.
Another area that will determine which quests to run is what kind of loot you can get. Many quests have obsolete loot. E. g. raid loot. For the shard, seal, scroll kind of epic loot I would skip those and instead introduce new epic loot that will drop directly. So you introduce an epic Sword of Shadows which can drop in the epic Plane of Night instead of having to hope for the seal, scroll and shard to drop.
Loot from quests should at least be as powerful as what you can farm at the same level. It doesn't make sense that you can only get +7 gear and insightful +2 with comms from King's Forest for level 21 while you can craft +8 gear and insightful +3 gear at level 15.
I would also make some special gear that are not necessarily directly powerful, but very handy for players. The Jibber's Blade is a very good example of such gear. For that item I would make it drop as a saga reward from Epic Three Barrel Cove in addition to just Two Toed Tobias. This way you get get a chance at the item via running all quests in the area and not repeating the same over and over.
Other items that should be able to get via saga rewards are Teleport items like the Key to Eveningstar, Bottle of Mist to Ravenloft and Boarding Pass to Sharn. Maybe you can introduce items who can summon rest or repair shrines etc. Such items now can only be purchased from the DDO store or drop as a dice roll. It would be nice to have a chance to get them in a saga reward list too. Not every time, but a chance for them.
The point is to encourage players to finish Sagas and get the highest tiers of favor. That means running all quests in an area instead of just the ones with the most XP.
I see your point(s) & I agree & disagree. I however don't think, (just speaking for myself mind), that I should forced to run quests that 1. I hate. 2. I don't know. And 3. That I have never had an interest in running ever. Though seeing your ideas would be very much intriguing however.