once you got passed the fact that darth maul "survived" being cut in half - a death im sure lucas would have retconned if given the chance - his involvement in the clone wars was a welcome one. he brought a level of raw violence that wouldnt have been as convincing with a new character as far as its relation to an existing one went.
but theyre really running with the maul milk now it seems, and maybe it's just because he was for all intents and purposes canonically dead for 10 or so years, but it's more bothersome than any other character at this point (now that EU is dead and sheev clones arent a thing anymore). i saw an article the other day with the headline "how darth maul became one of the series most iconic villains" and my first thought was how none of it wouldve been a problem if his "death"was more ambiguous
I mean, I would actually say that Clone Wars' storyline of Maul surviving and turning into a crazy junkyard spider was a bit too silly tbh, but as long as he's here, doesn't it make sense to end his story? They're going to tell Darth Maul's last moments at some point to close out that storyline, why is that actual story finally coming up 'milking it'?
I don't understand what the difference for you is with Maul being in Clone Wars and him being on Rebels. It's still made by largely the same team, and his story never really got to a close on Clone Wars. Honestly sounds more like your distaste for Rebels and admiration for Clone Wars that's the problem here. I personally never really cared for Maul as a character, but, having brought him back to life in the cartoons, it makes too much sense to bring that story to its natural conclusion. To the point where it'd be a shame if they never got to it.
Having that moment be against Guinness Obi Wan during his Tatooine exile feels like a fun and good reward after years of Maul's story unfolding, and it fits perfectly with his character/arc. I mean, if you're going to release extra media besides the movies to explore this world and its characters, surely they should be able to actually use those characters? It's not like either Maul or Obi Wan have been dominating Rebels, the show is still mainly about new characters and stories.