For people reading along, Peter routinely says "we" will do things that he hasn't built any kind of consensus for at all, so I'd take things he writes with a pinch of salt.

I don't have any intention of filtering script types in the bitcoinj implementation of the payment protocol. If a merchant wants to use an exotic script type then it's up to them to get it mined (that's why you can submit transactions directly). I also don't intend to make P2SH used by default, indeed, bitcoinj does not support P2SH transactions at all today and nobody has ever complained. So requiring P2SH transactions is a long way from happening, if it ever happens at all. As pointed out, it imposes "only" a 15% bloat on the block chain.