1. Better high-ISO;
2. Built-in EVF;
3. Tilting LCD;
4. MF Peaking display;
5. Vertical grip;
6. Power adapter;

Not sure if a CCD can refresh 120 times per second. A CCD will also require more power and more board/circuit complexity which will boost price, reduce battery life and increase size.
Yes, CCDs used to have better dynamic range than CMOS, but with latest advancements that's hardly the case (remember latest Sony sensors are CMOS too).
I've been thinking about variable doping between adjacent pixels....sort of Fuji's EXR, but based on different junction properties rather than different sizes....

1. Better high-ISO;
2. Built-in EVF;
3. Tilting LCD;
4. MF Peaking display;
5. Vertical grip;
6. Power adapter;

Here's a question for you. How much larger than the E-P3 will your fully equipped E-P4 be? Looks fab by the way.

How much larger than the E-P3 will your fully equipped E-P4 be?

Just a bit taller, I guess.

Yes CCDs suck at video, hence a big reason why we see CMOS now.

Not really and not the only reason. The famous 3-CCD at sony's camcorders was in fact CCD-based.
I believe we see CMOS now because of the higher integration level it has.
I.e. most of the related parts are inside the sensor chip, which leaves less to be added at the board level. Also having a lower number of interconnects and solder joints makes the device cheaper and more reliable.

Olympus still seems to be breathing contrary to a lot of crap flying around the forums. If they can survive the current Japanese economic slump I could fantasize about an E-P4 with a hot up to date sensor, some kind of high-speed-burst auto HDR mode, built in GPS with metadata stamping, wireless remote with full exposure control and intervalometer functions, a body that feels more Canon or Nikon than Plasticsonic and some kind of external battery/grip solution. I think a tilt screen would be nice too. It could still come in smaller than a GH2.

In order of highest preference first:
1: reliable continuous depth tracking AF with continuous shooting - then it would really enter "DSLR replacment" territory.
2: High resolution screen (920k dots or better)
3: tilt screen (thinner and smaller border than on E-PL3)

I don't have a problem with the existing sensor myself, but would not say no to any improvement. As a wildcard, I'd like a "beyond bayer pattern" sensor.

When people hear "Olympus", they think quality camera..
When people hear "Panasonic" they think television, radios, etc.....

Not that Pany is incapable of making great cameras, but there is something with all of their models, that just isn't right for me....

Probably why you & I  both own Olympus bodies....

Adash said it in the first reply and so did I later on.

I'll be fine with a 90 degrees upwards tilt.

new sensor filterless gapless baclit design with advanced well design that captures reflected and incident light  better 16-24 mp

great high iso and dymnamic range , transparant and excellent hdr implimentationthat has parameters that can be modified by the user

a much bigger battery ...side mount twin ds slots,   mike inputs miniplug outputs

keep the ep3 successes menus and focusing speed 

evf internal side mount and a flash [ fuji did it]

small great res lcd or oled

less leather wrapped around 
[more like the contaxg1]


visual mf assist on screen or evf

I think the number one desired item would surely be a new sensor. Although Fuji does not appear to be interested in the the µ4/3rds market for their own cameras at this time, it would be very interesting indeed if Olympus were able to develop a new µ4/3rds sensor in conjunction with Fuji. Improved high ISO performance is most often mentioned, but oh, that Fuji color would be delicious.

After that, my impression of the most desired item for the E-P4 is the tilt shift screen of improved resolution.

A better tracking AF system would be of interest to the still photography user segment and especially so to the video user segment.

After that most items fall into the refinement of the controls and a little tweaking of the shape for the purpose of camera handling.

Olympus, and Panasonic for that matter, need to be careful not to let the size of the body grow much, if at all, because one of the major attractions of the µ4/3rds system is that it is small enough to take almost everywhere almost all of the time, unlike a Nikon or Canon DSLR system.

In order of highest preference first:
1: reliable continuous depth tracking AF with continuous shooting - then it would really enter "DSLR replacment" territory.
2: High resolution screen (920k dots or better)
3: tilt screen (thinner and smaller border than on E-PL3)

I don't have a problem with the existing sensor myself, but would not say no to any improvement. As a wildcard, I'd like a "beyond bayer pattern" sensor.