I think I understand what you are trying to get at. Is it reducing the unspent transaction output set by doing a many to one transaction under a single key?

It is true that UXTO is growing. You can see that here:

http://statoshi.info/dashboard/db/unspent-transaction-output-set

But remember, one could even hand craft any flavor of transaction and submit it to the network. but any transaction is worthless unless miners pick it up and hash it into the block chain.

I suspect you are talking about transactions that are small relative to the transaction fee, so miners would ignore them.

But maybe I'm not seeing your point. At any rate, happy to see someone digging into the docs.