I have studied it, I see major problems in the future if nothing is done, and that is why I'm posting about the topic to begin with.  Here are the relevant facts:

1) Without trust, you must currently download the entire blockchain in order to get a pruned one.  (Note:  I know a lot more about pruning than this and the rest is not relevant. I'm willing to discuss my knowledge in another thread but here is not the place.)
2) As the blockchain grows in total size and pruning software improves, more nodes will switch from full mode to pruning mode.
3) The full blockchain will only ever grow, and will grow proportionately to the number of users using it.

Points 2 & 3 combined are the most worrisome, as less nodes to deliver more data may mean that 1 will become virtually impossible. 

For example, we currently are at a 60GB blockchain with 500k addresses.  Imagine 500 million addresses.  Since the blockchain can only grow, with those levels we can expect very quickly a 60TB blockchain.  If you have a 10MB/s (that's 80Mbps) internet speed, it will take nearly 69.4 days to download the full chain as you prune it along the way, and that's not even counting the 10,000 additional blocks that have been added along the way.  Furthermore, that assumes the full nodes have the bandwidth to support those speeds and that you were able to keep them up 24/7.  More realistically you'll be competing with 10's of other downloading clients per full node since the number will increase proportionately to the total blockchain download time multiplied by the number of users downloading a partial/full node.  In that case, most if not all will cancel the download part of the way through, meaning no one EVER gets the full chain.

Introducing Pruning Blocks into the blockchain will eliminate this problem entirely, and in the process improve download performance for the full chain because only those users desiring to run a full node will actually need to download it.