I generally don't have a specific opinion in this debate between block increasing fans and the opposite, but just to say Blocks are full is an exaggeration, If you use the default fees you are more likely to get your first confirmation with the first block i.e blocks are not necessary full at least in most of the time when there is a spam attack.
One look through old threads when SatoshiDice used to spam the fuck out of the blockchain until they were priced out via fees makes you understand that the chain can fit way more legit transactions if businesses optimize their transaction policies.
One good example is how fucking finally Blockchain.info decided to add dynamic fees to their withdraws. Considering just how many services use their API (for better or worse), I'd say this is an important optimization.