I don't think Telex is the right approach, but it offers one important benefit over the proxy approach: deniability. It may be true that regimes don't block all proxies. But if they decide to check up on you, they can see that you are using one of the censorship evasion proxies and punish you. With Telex, it appears that you are communicating with a legitimate web site; the only way to know otherwise is to crack the encryption and see that there's a message intended for Telex.
Getting help from ISPs isn't the only way to accomplish that. For example, if you could convince major players on the internet to run Telex-like systems _on their own machines_, then a user would have deniability because they could claim they were using the legitimate services on those machines. E.g. this might be a nice thing to put Google's 900,000 servers to work on, and would be a nice payback for last year's China hacking scandal.. Or something that all American universities could do in the name of free speech. The obvious way to block such a system would be to block the hosting site, but that may force the censor to cut off access to useful material (e.g. the teaching content on American university sites).
But it doesn't stop there; a censor could set up an SSL proxy and force all https traffic through it, which would allow them to decrypt any communication and look for suspicious side-requests. That's why we built a system a few years ago that disguises the subversive request in plain sight as a sequence of standard web browsing requests (and hides the response in images), without relying on SSL at all.