I've been idly toying around with posting the maths on this one....guess this is as good a time as any.
First let's pick a quest. Something with a nice high xp take to really show the numbers well. Someone recently mentioned Shadow Crypt and since I love running it. Let's look at closely. First off, let's NOT look at the optional xp for rares. i know it's where a lot of the early rep xp comes from, but the completion bonuses and elite streaks are what we are more concerned with here.
Shadow Crypt (Base XP as per DDOWiki): Normal/Hard/Elite: 9,820/10,360/10,900
Traditionally accepted quest grinding model: Normal x8 (down to 50% xp take), Hard, Elite (for first time completion bonuses and no repetition penalties)
Old First Completion XP Bonuses: 25%/25%/50%
1.25N+2N+(.9+.8+.7+.6+.5)N = 6.75N
6.75N+1.25H+1.5E = 6.75(9,820)+1.25(10,360)+1.5(10,900) = 66,291 + 12,950 + 16,350 = 95,591
Revised Grinding Model with the Elite put first to maintain streak but followed by Normal Runs for Speed:
**Assuming no xp loss for being overlevel. So pretend you're running the Elite at one under level.
Elite, Normal x7 (down to 50% xp take), Hard
New First Completion XP Bonuses: 25%/40%/80%
Bravery Bonus on Elite: 20%
Full Elite Streak Bonus: 50%
1.25N+1N+(.9+.8+.7+.6+.5)N = 5.75N
2.5E+5.75N+1.4H = 2.5(10,900)+5.75(9,820)+1.4(10,360) = 27,250 + 56,465 + 14,504 = 98,219
This appears to be a hefty enough increase, 2,628 extra xp and one fewer run....
...but let's look at that in context. What if we ran the old model progression with the new completion bonuses?
6.75N+1.4H+1.8E = 66,285 + 14,504 + 19620 = 100,409
That's even more XP than running with streak (albeit with one extra run in)!!
What about if we pulled one run out just to make it a side by side comparison? That would be the .5N run.
6.25N+1.4H+1.8E = 61375 + 14504 + 19620 = 95,499.
Less than the streak total, sure, but how much less? 3% If you don't earn MAX ELITE STREAK or BRAVERY BONUS at all. Over the same number of runs....you only miss out on 3% XP.
The point I'm trying to make here is that if you're going to milk the quests anyways, then streak doesn't really count for a whole lot. If you're only 'once and done' on the Elite streak, then sure you're coming out a good deal ahead, but let's examine that from a different angle.
Bravery Bonus and Max Elite Streak counts for 70% of the base XP. When it's all said and done, that's not even as much XP as you would pull on one full extra run without them.
All in all the Elite Streaks add more XP, sure. but not enough to matter, really. The real bonus was the jump in the first time completion bonuses. And that works for everybody every time, no matter what order you run your difficulties in.