miners will pare down block sizes for maximum verification times and propagation times.
I agree that it could be a positive outcome but I "prefer" my option for 2 reasons:- The theoretical reason: there's no solution faster than no validation
- The practical reason: from the recent fork, we can see that some (many ?) mining pools prefer no validation than paring down block sizes (e.g. F2Pool mines small or big blocks).
what's interesting is that we've never seen it done to the degree it is now. we had the Mystery Miner a few years ago but he stopped it pretty quick. also, despite many upgrades added to the protocol previously, we've never had a fork as a result of SPV mining before either. what's different this time is the consistently full blocks and the fact that Wang Chun told us they create SPV blocks in response to large blocks as a defense. it seems they consider full blocks large blocks so the excessive SPV mining created last nights fork in light of BIP66 and the upgrade to 0.10.x. so in that sense, the 1MB cap is the direct cause of what is happening.