if Olympus had improved the autofocus, manual focus and the RAW write speed to the level of what is currently available in digital SLR's they would have an absolutely brilliant camera and I would not need to look at buying a digital SLR for these crucial features. As it stands it is brilliant for travel photography but for portrait work it can be a pain due to the focus and RAW write issues and rather than address these issues, Olympus appears to have decided to concentrate on development of their digital SLRs.
faster CF read & write - 12-13secs is way too long to write a RAW file while locking the camera and browsing is slow. Why, oh why did Olympus decide to only have write speed of 1Mb/s??? can we PLEASE have a firmware upgrade to fix this?
increased buffer size to allow better shot-to-shot frame rates and minimise camera locking after photo is taken
better focus:
manual focus is not easy despite the magnified image - I do miss the optical SLR viewfinder with focusing screens
Olympus needs to fix the manual focus BUG - setting focus manually to infinity at wide angle gives focus at 3m while distant objects out of focus!!!
AF does not work on backlit subjects or low contrast subjects such as faces, and the poor manual focus means focus is very difficult if not impossible.
poor AF for action photos - this has been partly addressed by the newer Olympus C7070
the lens seems to be a touch fragile as it rocks around - I tend to leave the CLA-8 adapter on to protect it - it would be nice if there was an adapter for this that just allowed mounting of a UV filter which would then help to keep the dust and moisture out of the lens itself as well as mechanically protecting the lens from bumps.
a night mode option like on Sony which moves the IR-blocking filter out of the way so that better IR photos could be taken instead of the 1-3sec exposures that are now required
better RAW development software that allows 16bit files - although Adobe Photoshop CS 8.0 with latest plug-in works well.
software that allows a computer to be used as a LCD screen while taking photos
LCD screen swivel that works in portrait orientation and also in self-portraits - addressed by the C7070
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less noise at 400ISO, and if possible ability to take photos to 1600ISO with minimal noise, but I'm guessing this will only happen if sensor size is increased as with the digital SLR's.
better white balance menu system - it is too confusing to try and set tungsten or daylight rapidly unless you remember what you have assigned to the 2 preset modes.
a 2x teleconverter to make it a 280mm f/3.5 lens rather than just 196mm f/3.5 lens with the 1.4x converter
a couple of extra millimeters space to allow use of a 58mm filter at full telephoto when using the 1.4x teleconverter, if you do use one, you have to be careful not to go to full telephoto zoom otherwise the filter will hit the teleconverter and the camera will turn off.
12-14bit RAW instead of 10bit, to improve dynamic range even further
have to set self-timer mode before each photo, can't this just be set for every photo?
2 second self timer as well as 10 second.
bracketed exposures require finger pressed on shutter release button for DURATION of photos, thus cannot do with self-timer or IR remote, surely this could be fixed.