I don't have any crystal balls, but Scott and I do talk fairly regularly, and I can say that he too is looking for the next project and the ones that will come after it as well. As he has stated in other threads, it is getting harder to do newly tooled locomotives for a variety of reasons ranging from the consumer market, the economy of creating and selling product, all the way to geopolitical issues that have changed the industry as a whole. No need to get into the details here other than to say this is not an easy business to be in, and the risk is fairly large.
However, the pages of this forum have often led to that next model, and there is some good reading to see what the market might be for something new. In the meantime, there is still work to be done on the Genesis and Charger locomotives but that is forthcoming. The FAs are moving forward into production as the next "new" model. The GP30 needs reservations. There is also a healthy collection of quality tooling to do new runs of previous product. There are paint schemes yet to be explored as well as the brand defining road specific detailing on many of those locomotives.
I would never say never to steam, but it is very, very difficult to do a great quality steam locomotive for the reasons stated above. We need 75 forum members to agree to a prototype and then actually follow through and order it. 75 doesn't sound like a lot, but the reality is quite different. If I had an extra $175,000 laying around give or take to guarantee a run of CNJ Pacifics 831-835 done correctly with the Wooten firebox, I'd do it in a heartbeat and hope that I could sell the 70 I didn't need by the time I leave this earth. The same could be said for the PRR K2 I mentioned earlier. Never done in O that I can find and just a nice change from the plethora of K4s on the market. I have two of the High Iron Sunset K4s of 2004 and they fill that void well enough. The K2 is a bit early for my modeling era, but I can always make up a good story on that "lone" survivor. Also, a late PRR D16sb would be a wonderful model to grace my layout and maybe could have a little traction as #1223 operated on the Strasburg for many years and currently lives across the street in the PRR Museum. However, to counter my steam dreams from Sunset I am finding a great selection of older 2 rail steam on the secondary market including older Sunset models that can be updated and preserved for a future generation.
For transition era diesels, I'd love to see a FM H-24-66 done correctly in O scale that I don't have to spend a fortune on in brass and then tons of time to get it to run well and paint it. Same goes for the RS-3. However, the challenge there is a technology one. ERR is not a new system (yes shocking I know). The boards are huge and when you factor in the speakers, the smoke unit, and the motor, the smaller locomotives are just not technically feasible in 3-rail. The 2 rail boards are much smaller and offer greater functionality, but these projects only move forward with 3 and 2 rail models to meet the minimums. Lionel did a nice job on the H-16-44, but I would have to rework it to 2-rail. The HH Alcos are a great suggestion, but too small to do with all the features that are expected these days.
On 2nd generation diesel side? I'd love to see the FP45 and SDP40Fs move forward with more of an interest in the SDP40Fs. However, if I could replace my ScaleKing FP45s, I would more than happy to do so. They are woefully inadequate for the cars they pull. However, the interest hasn't been there to get the numbers. Another personal interest would be the GP40P as I saw them in all their paint schemes during my lifetime. However, it is another niche locomotive that likely couldn't generate the kinds of numbers to move forward. After working on the SD40-2 for so long, I came to appreciate so many of the variations. There are several I'd love to add if a second run comes around and there are countless roads that this could be done in still. I see potential in the Alco Century Series even if I don't personally have much interest. However, Apache Railroad C420s or M424s would quickly find a home in my collection and C630-636 is just a cool huge locomotive to add to nearly any collection.
Modern diesels are a bit of an enigma to me. The Class 1 operators have settled on a few variations of the SD70 and the AC4400 and now the ET44C. Maybe I am not paying attention, but I don't see the variety I used to in the freight locomotives. The EMD and GE modern locomotives have been done and done well so often in 3-rail so I don't quite see the market for them. It seems the passenger locomotive market is more obtainable in the Genesis and Siemens locomotives. There just aren't great O scale examples out there. However, the prototype market for modern passenger locomotives has become a lot like the historical market for steam locomotives. A lot of small batches of non-standardized power from the likes of MK, Siemens, Alstom, and going back a few years to Bombardier.
Finally, I'll conclude this very long post in stating that I'd be interested in a new run of brass GG1s that have a better drive mechanism than the original run. I'd even be happy with a replacement drive to upgrade the ones I have. Add to that updated versions of the P5a in box cab and modified versions, a run of MP54s in PRR, PC, LIRR, and SEPTA, Silverliner and Arrow Cars, and finally a scale Metroliner and I'd be very happy. I wish the E60 would have gone forward too, but I'd be in for an ACS-64 too if it were ever offered.
Thanks for getting to the end of this long read.