To be fair, the "time travel" seems limited and of the 'closed loop' variety which I'm less worried about (though I would rather they stayed away from that entirely). What I mean by that is that nothing suggests what Ezra did during the Ahsoka-Vader fight was actually any different to what had always happened. We know from the original Season 2 finale that A) Ahsoka is last seen fighting Vader, B) Vader walks away alone and C) Ahsoka is glimpsed disappearing into the ruins. Showing that Ezra did what he did in interfering via the portals doesn't mean he actually changed anything, but rather him doing so was always how we got from A to C. This is why Ezra could not save Kanan - when Kanan died, Ezra had already made the decision not to save him. Closed loop. Likewise, the Emperor says he wants the power to visit and change these pathways but we already know he doesn't get it because otherwise the past would already be different to what we have seen. Palpatine himself doesn't understand that the power he is seeking is truly beyond his grasp or else he would have already benefited from it. If we saw someone go back through the portals to, say, stop Alderaan from being blown up then that would be a different story since it would be a case of them actually changing the course of events rather than the portal simply being part of the course of events. Ugh, does that make sense? Even talking about time travel stuff makes my head hurt.