Maybe a strange question, but I was wondering why Trident is being developed. It looks fine and is working better and better, but I can't see what you want to achieve what isn't already in Zoho Mail?
Zoho mail is already an (webbased I suppose) app that provides access to mail/contacts/tasks/calendar etc.. Maybe it has something to do with future development or program structure? Trident seems to be a "real" app, not a view on a webpage.
And thinking a bit further, is the webinterface going to be updated to look like Trident? And, very important for me, is Trident going to be available on Linux?