Well Orochimaru is a smart man. He played along as long as Sasuke's demands didn't interfere with his own ambitions. Thinking Oro won't make his next vessel enhanced doesn't fit right. He'd most definitely want Sasuke's body at its peak when he takes over, give him stuff like poison immunity and all. I mean who in Oro's place won't do that. And don't ofrget Oro is quite persuasive when he needs to. Like he gave Sasuke a taste of CM power and he fell for it.
I agree Oro forced the CM onto Sasuke, but Sasuke had a choice just like Anko. Either to give in or to resist. He chose the former and went with Oro and that tells you something. Even though he didn't like to go with Oro, he did just that just to gain power quickly to kill Itachi. Again he didn't like CM when Oro gave it to him but eventually started to like the powers it granted him. I find the idea that Sasuke didn't take any drugs ridiculous and an attempt by fans to hype him even more. From the beginning Oro tempted Sasuke with powers like CM which is an enhancement and not physical training. Sasuke knew what he was signing up for even though he was unwilling to. And then Sasuke goes to Oro does just physical training...

He was quite determined to gain power as fast as possible, and for that he was ready to make any sacrifice. So just because he said he didn't like drug enhancements doesn't mean he didn't take them. And as I said Oro would want him to be in peak physical condition and would've done whatever was necessary to achieve that.
Sasuke had to wait for Oro to weaken to even attack him, so Sasuke was in no position to make demands which Oro won't agree to.