Since MTH is going to have DCS remotes again, lets hope they have the foresight to order lots of extra thumbwheel assemblies.
I get the sense they are simply building with what they have. The thumbwheel is one of the obsolete parts that they didn't have from what I hear. When I hear they're building "a couple hundred" remotes, it seems they may simply be using up parts stock.
I'm not quite sure MTH is building them. If they are building them here in the US, that would mean they would have a couple of hundred cases, screens and like on hand, and thumbwheels on hand, after MTH has already said they have no more thumbwheels available. I suspect it is another production run from China.
Which begs the question, why not build more than a couple hundred?
I'm pretty sure they copied elements of their remote design from the North Coast Engineering's (NCE) DCC hand-held cab, which appeared on the market around the same time. The NCE design is better, IMO, because their remote has a separate "Enter" button, so the thumbwheel is just for scrolling, and it's not "push to enter" which seems to be the source of many failures.
You can probably tell from my earlier posts in this thread that I don't like the ergonomics of the thumbwheel. My one and only DCS set is an original-issue model with the fine knurling on the thumbwheel. It's skipped occasionally since the beginning, and sometimes it's difficult to turn without inadvertently pushing it in. For a while, i took to operating it with a rubber thumb-grip of the type used for counting money. Always use protection! 
Every year at York I would beg Mike Wolf to redesign the remote, and a long time ago he alluded to a "different solution." First came the DCS Commander, which had better ergonomics, but it isn't a walk-around control, and is limited in its functionality. Now we have WiFi, Bluetooth, etc. Personally I'm not a fan. No tactile feel, and as I've seen on these boards, this approach engenders its own set of problems. But I can see the appeal to a younger generation that was born with a smartphone in their hands.
I'm actively planning a new layout, and individual loco control will be a cornerstone of its operation. If I were going to commit to the DCS architecture (and I'm not sure that I am at this point), I might just go the extra step and get a full NCE DCC system. PS3 locos are compatible out of the box. I could upgrade the remaining locos to PS3 or DCC as time allows. Another alternative is a direct R/C system that will work as long as there's voltage on the rails. At least one such solution has been under our noses for several years, and I'm confident it will work. Either way I've pretty much given up on the DCS remote, and without this key touch point, perhaps on DCS altogether. I'm starting to see that there are other ways to achieve the same end without as much frustration. My $.02.
