Similar to phone and battery elements, add "general infos" elements like memory, used memory, free memory (both for ram and sdcard), number of processes, ...
If the android API allows for it, in addition to current temp on could add max/min temp of the day.
Another element (related?) would be sun rise and night times, with the assorted moonphase/sun icons
Not sure it is part of the weather API, but other clocks gives those so it may be available
an optional time zone (numeric offset, or maybe by region if android API allows for it) could be added to time elements (both current numeric times, or possible future analog clock). This would allows for world clock designs (2 clocks with different time zone, quite handy when you travel or communicate a lot with distant peoples)
Have missed calls and sms in place. I know gmail notifer does not work for others like adw, but would like to have it in place when there is a solution
If u can fix to show a # when there is a message or missed call and not always a zero in place
Widgets like Beautiful/Fancy Widgets, or MIUI lockscreens, use images to represent elements of time, date, etc. It'd be neat to integrate a similar function in Chrono. so that times and dates could be displayed with more effects possible than text editing alone. Highly stylized flip clocks like this would be possible. :) http://melissapugs.deviantart.com/gallery/#/d4fhhax
A line or strip thats parallel with the status bar to represent the remaining battery life.
Add the next coming calendar events like in "smooth calendar".
If we could edit on our computer as well as on our phone, it would make stuff much faster.
A pinch too zoom and paning option may make the editing of small elements more easy. Maybe with a grid for placement, this would make accurate positioning of elements possible. But best would be a PC editor (see other idea)
The various stylistic options for the text - embossing, shadows, shading, etc - would be great if they could be applied to canvases and frames. It would make for possibilities of flip clock designs without having to use an image backdrop.