@hayhor People not finding LTMs may seem very stupid to us, but usability tests often reveal surprising things,I believe this was one of those. While this point alone can easily be addressed via UI changes, there are the other points that also matter.
I also prefer separate LTMs, but not because I feel forced. A separate mode can stray away from the regular meta, allowing for way more experimentation than a takeover. But I've seen the effect of the lobby fragmentation, so I understand and agree with their choice.