I dont think he was that bad but his performances certainly got more disappointing as time went on.
He and Kevin Spacey as Lex are probably the two greatest examples of where massive fan-service didn't exactly go well and get the results people wanted . Anyone who used to be on messageboards in the late 90s/early 00's knows everyone wanted Christian Bale as Batman and Kevin Spacey as Lex Luthor before we even knew anything else about when Batman and Superman were gonna have movies (00-03 that was the convo and Bale Dammitt was a meme) and they finally got their fan-service dreams.
That's probably why you see a lot of stubborness from people online to say he was wack. In his defense though, I feel like good or bad acting is entirely predicated on good or bad writing and the choices the director on set guides you through as an actor (Plus unlike theatre its a different medium where you can give 10 takes of the same performance and its up to someone else to decide which one works for their movie) . Goyer and Johnathan's writing in the trilogy always yielded varying results and some good stuff but plotholes. And Chris Nolan was probably at times so big on visuals with dense storylines that sometimes he forgets to co-sign things like Bale's voice (Which is a shame because he has gotten good performances out of unlikely sources like Hathaway and Ledger)
I actually didnt think it was a problem in Batman Begins and I barely noticed (Also the voice he used when he was in Gordon's office with the ski mask should have just been his voice) and he gave a strong performance. The gravely shyt became an issue in Dark Knight and rather than adjusting it for TDKR he kinda kept it and this was after people online had already made fun with it lightly for the last film and they just went to town on the second one as it was a noticeable.
I still think he's the most solid live action Batman. People will always say Keaton as a counter and to be nostalgic but you could probably find just as many problems with his performance if you wanted that where either his fault of Tim Burton's. Essentially at times, it felt like he was playing himself letting his eyebrows do the work. Sometimes the suit would consume and he looked uncomfortable in it that it felt like affected his performance. And I never brought the whole "YOU WANNA GET NUTS?!" scene he did in the first one as something Bruce Wayne would actually do. And I dont want people think I'm shytting on Keaton cause that is one of my favorite actors who is diverse as hell, but if we're gonna nitpick Bale, you could probably nitpick Keaton just as much.
Its tough because Batman isnt always the center of his movies and thats always going to happen because the Rogues, the city, the cops, the supporting cast are just as important in Batman mythology. So actors playing are gonna feel overshadowed and cut for time and sometimes the best stuff doesnt pull through. Still I think Bale gave the best Batman/Bruce Wayne performance in the one movie that focused on Batman the most which was Begins.
I remember when I was on
and people were discussing it when it dropped. The scene with Flass and he got him hanged up...in 2015 that probably gets laughed out the building but at the time when he said the "SWEAR TO ME and DO I LOOK LIKE A COP" line people were wanting a Dark Knight kinda Batman and people dug that and were like
.
But I bet if you advocating for Keaton in this thread...you might wanna go back and look and those movies as well with 2015 eyes as well and see if its really all good
it's the same question 
..... but still
