If you scroll back up you will see I address the max PL comparison and state since it is out of the scope of this topic I don't dive completely into it (but yes people should get free EPLs/Racial PLs/Heroic PLs to close the gap also). Your math is accurate, the true number is much closer to 1300 than 400.
I'm not lost at end game. I do not have, nor never will acquire the stat accumulation needed to get into the top two DPS slots of a R10 group. It is literally impossible for me. Even if I were to quit my job and life and spend 10 hours a day playing DDO every day I would still never get there because those characters in the top two spots of a R10 group have such an enormous power advantage the chasm cannot be bridged. There are no improvements to be made aside from accumulation, which many other posts have pointed out, is impossible without a catchup mechanic.
Here is a real-world example from yesterday running R10. I'm an L28 inquisitive, fairly powerful character. KC in Feywild, the group leader 60, FVS 25, Me 10, bottom three 5, 2, 1. When I'm in the 3 slot, R10 quests are going to be hard and they were, but doable. For me to even be in the 3 slot at L28 with still some heroic gear should dispel your notion that I need some type of "skill" improvement. I have all the DDO skills I need. It is now only about accumulation. Now, inquisitive is a fairly strong archetype and if I were L30 and had optimized gear I could probably edge up toward that FVS. But that gear is being nerfed (I'm fine with the nerfs btw but these things need to go hand in hand, hence the purpose of these posts) so really I won't be getting much benefit from L28 to L30 gear when the updates roll in. So how can I close the gap? Only through accumulation. If you see another way, I'm open to suggestions.