Few weeks ago the number of transactions increased as can be seen here:
http://blockchain.info/charts/n-transactionsAs discused in IRC this is not an issue at all, and it has been already documented in the original design paper of bitcoin.
http://blockchain.info/charts/n-transactionsBlockchain size increases rapidly, and this is probably not a problem for desktops or servers, but it is for embedded devices where the disk usage and cpu power are limited.
This is also a problem for new users because they need to download and calculate more stuff before starting to do anything with the client.
I would like to be able to use bitcoin from a pocket device without having to use a blockchain. Online wallets are not an option.
Another possibility i found is the possiblity to modify the client to accept a verified original new root for the rest of the chain. This breaks the design and can be dangerous.. But what's the option? A portable device can validate transactions, so it can check the blockchain, but why store it completely?
I don't really know a lot about the bitcoin source code internals, but I would be interested in having support for this.. or at least find a way to use lightweight clients.