The premise of the new series is a little shakier and weaker than the premise of TCW, that's for sure. As you said, none of these lead characters are seen in the Original Trilogy (nor mentioned) and there won't be a special emotional attachment or connection between the viewer and Ezra, Kanan or the others in that respect. At least with Anakin - even though he would fall hard to the Dark Side, turn evil and massacre a lot of innocent beings as he helped the Emperor seize power - you knew his destiny and you were curious about the events leading up to Episode III and his ultimate downfall in that film. We don't even know who will survive long enough to witness the full-blown Galactic Civil War of the OT (though this is Disney we're talking about and wiping out an entire animated cast isn't going to be their thing, so we can probably assume without much hesitation that at least some of these guys and gals will be alive during the time of the Original Trilogy) and we know none of them show up in the backgrounds of those films, so aside from being a bridge connecting the Prequel/Clone Wars era to the OT and containing visual nods it doesn't exactly provide many direct connections. All that said: it can still be a great show if handled correctly.