Extending Bitcoin to new and wonderful types of transactions is fine, and, actually, I believe Therilith could build most of what he wants on top of Bitcoin
I don't think you are interested in wonderful types of transactions, may be even the opposite.Now the rules are more strict and inputs are being checked for being standard too
We had the chance to enable more opcodes inside P2SH, but it didn't happened...
I'm against changes that might make Bitcoin a tiny bit better, but if you've got a well-thought-out proposal for how to make Bitcoin much better in some way then I'll help you argue for it.