"The sets I have seen at the LHS, have a basic DCS remote that allows operation in the DCS system, without all the bells and whistles. This allows a starter in the hobby to aspire into bigger and better products. Personally, my thinking is Lionel would have been wise to produce a basic system that would have fully integrated into the Legacy/TMCC system, allowing newcomers to move up in the product line."
The MTH starter sets are command ready, but not command capable without purchase of DCS (about $300). This is a much bigger obstacle to a beginner operating two trains independently than LC and LC+ not being operable by the Legacy system. You'll also need a second DCS remote ($150) to get equivalent functionality to a Lionel set and LC+ separate sale loco. If you buy two MTH sets or a set and a Railking or Premier loco, you do not have command control quite yet, not without DCS. You have two locos that cannot be operated simultaneously and independently, except in conventional mode on separate loops or blocks. In addition, by having the more capable PS3 loco in every starter set, MTH has upped the price by about $100 or more at retail beyond a typical Lionel set, which is not trivial when you're talking to folks just starting out.
Lionel's strategy is to have two levels of command control: LC/LC+ and Legacy. The first (LC) comes with each starter set and gives you independent control of the loco in any setting: conventional/Legacy/DCS. These starter sets have been priced at retail as low as $100-150, which is perhaps half the price of the typical equivalent MTH set. The MTH set admittedly also includes higher quality locos and rolling stock. But the price of Lionel can be much more beginner friendly. And the locos will operate on a command layout without additional expense.
Should you buy a LC+ loco, no additional expense is required for independent control of your starter set LC loco and your LC+ loco, compared with $300 for DCS for the MTH starter set and RailKing purchase. And you still only have one remote of any utility. So in practice, you can acquire two Lionel remotes and two locos capable of command operation for about $500-600 or less. This compares with a starter set (say $300) from MTH, a RailKing Loco (say $250), DCS ($300) and an additional DCS handheld remote ($150) for a grand total of $1,000 or so. True, the MTH stuff will be, on average, higher quality equipment. As it should be for double the price. But the realities of play value vs. market price seem remarkably in Lionel's favor in this analysis, at least to me. Worrying about whether Legacy owners will object to having a free remote or two in a LC+ purchase seems peripheral to their goal of providing command control at modest prices to the beginner to intermediate consumer.
Making a bridge device so that someone with Legacy can control a LC/LC+ loco seems inevitable, but not part of the original startup of this new line.