Your bloat is another persons smokescreen. I have been thinking about this very issue a lot. FST is quite large. I can forsee TRUST getting large too. Why dont coins start a new chain each year? I do the same thing for hard drives when they are bloated, I just go buy another Drive. Not sure what to call it, "Coin Migration?" Also if an old block chain is no longer needed, and was left to die, all transactional history would be gone as well.
At any rate, PoS coins are very easy to maintain, and old chain can be maintained for quite some time. Each new version of the wallet would include a 1 to 1 accessing the old wallet or some web application.