Curious as to why the frequency would matter, as long as each locomotive only responds to its own remote? If the locomotive is bound to a specific controller, as current radio control receivers are, the frequency then becomes irrelevant. If these are not digitally bound receivers, but frequency dependent, Lionel has claimed that each locomotive will operate independently with its own remote, so even consisting would be possible with both identical locomotives responding to a single common remote. So, in effect, this is command control "light" as I understand it. And command control "very inexpensive" one might add.
For simple layouts and simple minds like mine, I'm not sure this isn't all the command control I need at this point in life. I suspect they will continue to put Legacy in their high end locos, so you'll need Legacy or TMCC for those, but for everyone who focuses on the mid-range and lower cost locomotives, this system sounds like it's simple, inexpensive, and hopefully robust. I'm sure those with complex layouts and who want to use command control for routes, switches, accessories will still buy Legacy, as will those who are interested in the high-end locos.
One thought occurs to me. These locos, unlike TMCC and Legacy locos, will not be controllable, except in conventional mode, by MTH's DCS system's handheld. You'll need the Lionel remote that comes with the set or loco to operate these locos in "command" mode. You're pretty much locked into using Lionel's technology, which is probably a side-benefit to them of this marketing approach, not the main intent. You'd never get away with this approach in any other scale/gauge. Given the small number of vendors who offer a complete line of products (basically only MTH and Lionel), MTH has gotten away with it with DCS for 10+ years, and Lionel is now moving towards that model of a "closed system" (pun intended).