p2pool already does better than centralized pools by reducing orphans, paying out transaction fees to miners, allowing merged mining and not charging any fees. So hashers who adopt it and become full miners should already increase their earnings.
BTCGuild
pays for orphans, pays transaction fees, merge mines NMC, and charges 1.5% fees.
The bigger issues are: 1) awareness, 2) easy of setup/management, 3) compatibility with some mining setups (some specific ASICs don't work well and very small miners won't get consistent earnings). If you want to help with decentralization, contribute to working on one of these three items. Anyone who is interested, even without any programming or scripting ability, can help with 1)
And:
a) Increased disk space and IO requirements for the full Bitcoin blockchain
b) Increased CPU and memory requirements for running bitcoind
c) Increased network bandwidth requirements for running a full node
d) Increased variability
e) Increased transaction costs in later spending your mining income, due to the large number of small payments, rather than a single payment from a pool
For me, 1.5% seems like a fair charge to avoid those issues.
(To the thread in general) Stop assuming that people are being stupid or ignorant, just because they don't make the same choices you do.