I'm not concerned about the difference between cloud based or desktop based as far as storage. We're backing up everything to github, dropbox anyway, it would be nice to have local storage as well obviously.
The real difference between Bespin and TextMate, Espresso, Coda is performance. Text editors better be fast, Bespin is not there yet. Maybe it's hard to get good performance with HTML5 for this, but the example of TextMate, where people begged for a Windows port, shows it might be worth it. Relying on OS makers to keep improving OS developer APIs is a bad idea, everyone is focusing on light mobile OSs and browsers. It's sad to see great desktop apps become abandonware.
Source control GUI for github, FTP, easy deployment to various cloud services that support various languages, VMs would be nice. More importantly, adding features through plugin systems should be a snap. I had this idea where code can be organized in many different ways. CommandFactory belongs to Commands and Factories, but it becomes annoying to browse through deeply nested folders. Code should be organized by tags, not folders. Code inside a file could get tags too, so you can click those instead of scrolling. Don't know if today's IDEs could support this, but the plugin systems seem too complicated anyway.
I've tried Bespin, they've refreshed it and most of the features that made it awesome are now gone (for the time being). As nice as the editor is, I don't really have much faith in the project anymore. The problem (and also aspect that makes it good) with Bespin is that it uses the HTML5 canvas element. Slow as hell but it's only going to get faster.
I know what you're saying about speed. The goal with my editor since day one was to have it as speedy as possible. I won't settle for mild slowdowns under 5000 lines on a netbook. This is unacceptable considering it is a big portion of the market.
I like the tagging system, it's pretty innovative but I don't think anything else is ready for it yet. Plugins are a good idea too. Everyone likes to write code in their one way.
Thanks once again... :-)
So although I wish you luck and am hopeful that we will perhaps one day have a usable cloud-based IDE, still kind of doubtful that it can happen with current JS engines.
This is a "Class A" problem, and big players are going to spend a lot of bucks in this field. As indicated by mozilla working for years on this product already. So I would say be prepared to go big if you really want to address this need. This isn't really a product for a small lifestyle company.