What IS unrealistic however is... how fast he went from suspecting Palpatine was a Sith and siccing Mace on him to betraying the Jedi. I still don't get that. Anni knew the Sith were bad news and liars or at least corrupt. He's just rooted out one of the biggest Sith who is blatantly tempting him and said Sith is literally there shooting lightning at Mace and losing... and Anni suddenly turns? It could have worked if they had given a few more scenes to Anni's temptation and fall and the whole thing ended up being a trap/set-up, but as-is it came right out of nowhere.
Yeah, to be honest, the Star Wars prequels really could've used better writing/directing in many parts, including that one.
I actually liked The Phantom Menace (and am a subscriber to the "Darth Jar Jar" theory), but even I can admit that it needed better story direction. George Lucas should not have done it on his own.
That's why the Original Trilogy is still so highly praised by many (though, to be honest, I actually hated "Empire Strikes Back"). George Lucas had help. ---