Roughly once a month for about two years now I've entered, Logitech "new wheel" in to Google to see if there is any news of a successor to the G27. That's exactly how I came to be on this thread today.
I've read this thread from start to finish. Depressingly I don't think Logitech will continue to make wheels, and the post a few pages back (I forgot who made it now) about Intel stopping desktop processors and pc's getting watered down is even more upsetting.
I believe a small part of the problem is the fact that the G27 was not a worthwhile upgrade for those of us who already owned a G25. I remember following the pre-release hype before it came out and read all the reviews once it did.
First thing that put me off is they got rid of the sequential shifting option. Two things about that is 1) I drive a variety of different car types and I like to have the option between paddle, sequential and gated shifting. 2) I am a cross platform gamer, the G25 was also PS2 & PS3 compatible, so for my older games (and PS3 games that don't support the six speed shifter) I was forced to use the paddle shifters.
Secondly because of the helical gears used, the force feedback deadzone around centre was allegedly worse. Also (I may be alone on this) I think the G25 is more aesthetically pleasing than the G27. A lot of the improvements were reportedly fairly small, so I held off buying one and waited to see what Logitech's answer to the offerings from Fanatec and Thrustmaster would be. But one never arrived and now it seems may never arrive.
I have seen quite a few people in the same boat as me, wanting to buy a new wheel but waiting for a successor to the G27 before making their move. I believe Logitech lost sales from people who wanted an upgrade so either, still haven't upgraded (I still have a DFP and my G25) or bought from another company.
At the moment the company that is exciting me the most is Fanatec. I like the fact that you can purchase the parts you want to make the setup you want. I also like their idea (although I thought of it first) that you can swap the rims. I however hate the gear shifter mounting on to rails idea (TABLE CLAMP!!!) and the fact that you need about 5 yards clearance for a desk mount (some of us have keyboard trays. In fact I can mount my Logitech wheels without disrupting my pc gaming setup at all).
Thrustmaster have got on my nerves a bit, They had in their description the fact that the rim could be removed for replacement rims. Then no information for ages and ages and then.... An F1 wheel, damn! (unless F1 is your thing it is very expensive and and of little use for anything else) I was personally hoping they would go with either a nice leather wheel or something like a Sparco or Momo. The fixed paddle solution was also very off-putting for me, as I said I like to drive different car types so for open wheelers and F1 (which I only occasionally drive) your only option is the F1 wheel.
I hope Logitech continue making wheels but my gut tells me otherwise.