Ok, let's discuss this again - moved to future development forum.
This suggestion would mean that the preferences window needs to keep the count of disabled filters for each subscription (recalculating it every time it is needed is certainly not an option). This count needs to be updated when filters are disabled/enabled, moved or deleted, when subscriptions are updated, probably in more situations. Making sure that it is correct under all circumstances sounds like a tricky affair, will certainly add some complexity to the already overly complicated code.
Conclusion: At the moment I cannot see the big gain that would justify this. But I will be happy to learn otherwise.