Would it be possible to "buy" task points with exp?
Let's say 1tp for 1M exp... most powerful player in game has about 6-700M exp
now? 600M exp would then mean 4 full boons, which could be viewed as an
alternative to 2-3 (or whatever) rebirths to get a more powerful race...

Finally, this would stop all future whining about boons ("shut up newbie, go
make exp!")

umm 600tp = 4 full boons ? yeah right ,)

You can already buy TPs for money from the shop and by bribing players who are
willing to sell TPs. There shouldn't be an unlimited number of something
that's so good