It does matter where RSA-1024 is being actually used in Tor. As far as I understand, as long as it's not for some long-term keys, it still shouldn't be a problem. Please write if you know more on this subject.
I'm not an expert on Tor code, so I can only speculate and agree partly with you: it matters where it is used. But temporary keys do not necessarily help against an attacker who has access to all/most past Tor traffic. RSA-1024 is used in node identification and hidden services, the weaknesses are known:
