I spent a lot of time trying to simplify the process, but I agree that it still isn't something that Gavin's granny could handle.
I have no illusions about anyone's grandmother executing this process. Nor doing regular offline transactions. But there is a large class of users for whom this is the first usable solution without having to understand tx structure, UTXOs, change outputs, etc.
The only difference I see is that you have a central point that collects the signatures from all the parties, whilst in my case people come to add signatures one after another and the last one to sign can just broadcast the transaction out.
There is no central authority -- it's fully decentralized. One person/device prepares the transaction, and whichever device adds/imports the last signature can broadcast it. It is passed around as ASCII-armored blocks of text that can be emailed, and/or copied to USB to take to offline devices. We
would like to add a central server that would help users pass the data around, further improving the usability for those who want it... but the decentralized solution would always be available.
P.S. -- This is what people pass around to collect sigs (either inline in emails, or save to file):
=====TXSIGCOLLECT-4ogNaap7======================================================
AQAAAAsRCQcAAAAAAf1OAgEAAAALEQkHX/rr6vit6h6hFEtrSevRUWb0ev79VNLukkIjNUNoZj8AAAAA
/QABAQAAAAEGOwaI7hG2eALnVRhP5U9htkL5nR7pkmuhA++lkvmwjgAAAACLSDBFAiALPCTF3jPh238+
0TRiv7078ukWSykh5etoOC92mgHUtgIhANoaevyjicUcXZrBG4B05MCe0b6Ao4oQF1MWratKk51XAUE E
ziXsxcDUeorfEALx23AQ7/850SCxb/a+ZxbqIQ48ExhQgyCnQRF8ljIqOHz+5p7nJrWdfhVy2vtwICfz
vFbMff////8CQHh9AQAAAAAXqRTllz72+r9S3h22NtdNbPS0W/TqhofAcCc0AAAAABl2qRRJvTihhk4j
NbkfeRLljm0F7x58aYisAAAAAIdSQQRaVaMnjUAAEwZ8WtKXeCYt1UlDBNmX3woLIHwh2+sDB8xs5nqY
6iygkHrJZMSUJncnX/g29PgFrv9Sco2BZKh/QQSTtOSfxz3CHvwktSKnps0SiTZwzoLBqyuju1BawtJn
5FvVUfOSJGjflmvJVB8A3Kk6IIbdW14wv8/YpL4yZpfsUq4ISHVla2pwcEwA/////wJBBFpVoyeNQAAT
Bnxa0pd4Ji3VSUME2ZffCgsgfCHb6wMHzGzmepjqLKCQeslkxJQmdydf+Db0+AWu/1JyjYFkqH8AAEEE
k7Tkn8c9wh78JLUip6bNEok2cM6Cwasro7tQWsLSZ+Rb1VHzkiRo35ZryVQfANypOiCG3VteML/P2KS+
MmaX7AAAATQBAAAACxEJBxl2qRTAJVPUOGJ3S2BllgR6HNc32I8NloisMFF9AQAAAAAAAAROT05FAAA A
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