So, the P2Pool is the pool of the future of Bitcoin.
I'll work to make it even more easier to use.
Great the project could use more dedicated developers/promoters.
One thing to keep in mind is that variance is higher w/ p2pool especially for small miners so it may no be ideal for everyone. P2pool needs to ensure the network (as a whole) doesn't produce shares too quickly. If two shares are produced based on prior sharechain share then there is a network split (much like Bitcoin).
To avoid that the p2pool network raises share difficulty based on network hashing power to keep average share time at 10 seconds. If p2pool got very large this would result in a very difficulty share. Your avg time between shares in sec = (10 * p2pool hashrate)/(your hashrate) So if you make up 1% of the p2pool shares will take about 1000 seconds or ~ 17 minutes. If p2pool every got very large this could be partially mitigated by an improved protocol which grouped miners into smaller "sub pools".
And about merged mining... I care too much about Namecoim. It can be done with P2Pool (Bitcoin / Namecoin)?
Currently p2pool doesn't support merged mining but there is no technical reason it can't. Technically one could even make it option (user makes a choice to turn merged mining on or off).