Hear me out here, this is a great idea to get more TP and promote TRing. I'm sure it has nothing to do with PnP, but this is ddo. This is also my first suggestion, so go easy on me.
Awakening - Selectable feat for all classes.
o Prerequisite - TR only, and only available after use of a +2 tome.
o Discription - After developing skills long forgotten, you mind and body remember more of you past life than before.
o Allows - It opens up an enhancement line for your lost +3 and +4 tomes.
-Str awakening 2 AP - Your body coils with strength after long past lives are remembered. You gain +1 str (if you had access to +3 tome in past life)
-Advanced Str awakening - 4 AP - You body remembers past days of glory and you gain an additional +1 str (if you had access to +4 tome in past life).
-Dex awakening .... you get the idea.
You would have to eat a new +2 tome, select the feat, and take the enhancement lines to use your past tomes. If you ever pulled another +3 or +4 tome, you could reset enhancements as needed. You could take as many awakening enhancements as you had tomes. They would be available at the same level as a +3 tome, or +4 tome.
Pros -
More TR = More TP
More +2 Tomes = More TP
Plat sink with all the pots and gear needed
Keeps players playing longer
Players will still grind for another +3 tome to swap feats = More TP (if buying the shard)
Older players may buy missing lower level packs = More TP
Lots of Happy TR's keeping old tomes
Cons -
Less capped toons?
You have to select the feat
You loose AP
You have to eat a new +2 tome