Perhaps the bitcoin economy has matured enough that a set max block size is not actually needed anymore?!

What if we had some type of patch that eliminated "silly sized blocks" and allowed miners to set any soft limit they want? Have it something like: allow any size as long as it's not more than x3 (or other number) the previous months average block size.

Market incentives will drive each mining pools soft limits. Increasing the limits will stimulate growth (increase centralization if done too fast compared to technology because of resources needed) while smaller blocks will increase fees. Some may like smaller blocks because of risk of orphans while others will want large blocks to grow the user base of people using bitcoins. Allowing a x3 size block means that as long as a minority are making small blocks, those who want larger ones can still help grow the "silly size" limit and those who have weak internet connections just have to download the blocks and can continue making small ones.

A spam attacker could only create large blocks that were bigger than all the pools soft limits only by mining it himself and the largest block he could create would be a x3 of the blocks on the system. And just like it's in their economic self interest to not get bigger than 51% it would also be in pools own self interest to not have a soft limit that would risk too much centralization of the system by making it too large for current technology and allows for the system to rapidly adapt at the time. The fact that most mining is done by pools means that the soft limit can be more fluid.

Ultimately if we let pools set any limit they want would they set limits that would allow bitcoin to thrive? If we assume the majority of pools act in the interest of a growing decentralized system would max block size be needed anymore other than something to prevent a "silly size" block?